Nitrogen Cycle

The most common mistake that many beginning tropical fish keeping enthusiasts make is to stock a new tank with as many fish as possible without first establishing a healthy, stable, ecosystem in the aquarium. This is done through a natural process called the Nitrogen cycle.

Nitrogen Cycle:

All fish release toxic wastes that in an enclosed environment will eventually contaminate the water in the aquarium. Uneaten food and fish waste in an enclosed system will break down and release toxic ammonia into the tank water.  In a river, lake, or stream, the amount of ammonia created by the fish is negligible but in an aquarium, it can quickly become lethal.

The Nitrogen cycle is a natural two step process that establishes colonies of beneficial nitrifying bacteria (Nitrosomonas) in the aquarium that metabolize toxic compounds and renders them harmless to fish.

The beneficial nitrifying bacteria once established in the aquarium will convert toxic ammonia into Nitrites, which are less harmful to fish.    Although Nitrites are not as harmful to the fish as ammonia, they are still toxic.

After a sufficient number of Nitrites appear in the tank, a different type of bacteria , (Nitrobacter)  will begin to develop that will convert the Nitrites into Nitrates which are generally safe for most species of fish.

Excessive Nitrate buildups can also cause problems in an aquarium but are easily controlled with regular tank water changes.   Floating and submerged plants use Nitrates as fertilizer and are used to control buildups.

The entire Nitrogen cycle process can usually be accomplished within a month, but can take as long as two months to complete.

An aquarium is considered completely cycled when it contains zero traces of ammonia or Nitrites; and a minimal amount of Nitrates.

Speeding Up The Nitrogen Cycle:

Because most tropical fish keeping enthusiasts are impatient and want a beautiful tankful of fish as soon as possible, they naturally want to know if the Nitrogen cycle process can be accelerated. The answer is YES. There are several ways to safely speed up the Nitrogen Cycle process.

The safest way to accelerate the growth of beneficial bacteria and speed up the Nitrogen cycle process in a new aquarium setup is to add water, gravel, and aged filter media from an aged, already established aquarium.

Transferring some gravel and/or up to 100% of water from an established aquarium will significantly reduce the amount of time it takes to cycle a new system.

Adding “seeded” filter media from an established tank will dramatically decrease the amount of time it takes to complete the Nitrogen cycle process from several weeks to only a few days.

When using the “seeding” method, it is important that only HEALTHY established tanks are used for the transfer of beneficial bacteria. There is always the possibility of introducing unwanted microorganisms, parasites, and even disease into a new system when water from a “sick” or previously treated tank is used.

Aquarium starters of live beneficial bacteria are sold in most pet shops as a way to “jump start” and reduce the time it takes to complete the Nitrogen cycle process. Live bacteria help boost the biological filter in new systems, destroy sludge buildup in the gravel bed, and help to keep plants and aquarium glass clean.

The effectiveness of using this method depends entirely on the freshness, quality, and amount of live bacteria in the bottle. Some tropical fish keeping enthusiasts swear by this method, while others prefer the natural cycling method.

API StressZyme, API Quick Start, Fluval Biological Enhancer, and Aqueon Pure Bacteria supplement are a few products that are available.

We have found from many years of experience that allowing the nitrogen cycle to take place naturally results in a more stable aquarium. Using beneficial bacteria to “quick start” the Nitrogen cycle is effective but can lead to an overly imbalanced aquarium.

Fishless cycling:

Instead of introducing live fish into a new aquarium setup and waiting for them to create ammonia in the tank; some tropical fish keeping enthusiasts choose to cycle their new systems using ammonia chloride or ammonium hydroxide.   The idea is to mitigate stress and the potential loss of fish during the cycling process.

Although this method results in a very stable colony of beneficial bacteria, it requires a lot of patience and water testing.

To cycle a new tank without using fish, you will need a source for ammonia, a water testing kit, de-chlorinator, a heater, and a filter that you will be using in the new tank.

First fill the tank with de-chlorinated water and set the water temperature to about 85 degrees F.

Next, slowly add ammonia chloride or ammonium hydroxide a few drops at a time until the the ammonia level test reaches 3ppm to 4ppm. Add only 2 or 3 drops at a time over periods of a half hour or so to allow adequate dilution. Do NOT use ammonia products for home use that may have other chemical additives. The other chemicals are often deadly to fish.

Make daily water tests until the ammonia levels in the tank drop down to around 0.5ppm – 1ppm; then add more ammonia to bring levels back up to 3ppm to 4ppm. Continue doing this daily until the nitrite levels start going up. This should take only a few days.

Continue daily testing for ammonia and nitrites.   After a few weeks the nitrite levels will begin to drop. When the ammonia and nitrite levels both show 0 ppm, the nitrate levels should be going through the roof. When the Nitrate test readings get up to 30 ppm, make a 70 to 80% water change to bring them down. At this point, the beneficial bacteria should already “seeded” into the aquarium filter, aquarium gravel, and decor.

Next, add a final dose of ammonia to bring the test level up to around 4 ppm and wait 24 hours before making another test. The readings should then test 0 for both ammonia and nitrites.

At this point the tank is fully cycled and fish can be slowly added to the system. Be sure to continue testing after new fish are introduced to ensure that no sudden spikes occur.

Cycling with fish:

Most tropical fish keeping enthusiasts use hardy fish like Zebra Danios to cycle their aquariums. This method requires constant water changes and daily testing of ammonia, nitrite, nitrate and pH levels.

First fill the tank with de-chlorinated water and make sure to use both a mechanical and biological filter.    These hold the largest amount of beneficial bacteria.

Start the Nitrification process by adding one or two hardy fish per 10 gallons of water into the aquarium until the Nitrogen cycle is completed. The fish waste, uneaten food, and nu-noticed dead corpses will create the ammonia necessary to begin the Nitrogen cycle.   Additional fish can be gradually added when the tank is fully cycled.

Test the water daily for ammonia. Ideally, the ammonia levels should be maintained under .25 ppm. If you see that the ammonia levels go past .5 ppm, perform a 50% water change with de-chlorinated water.   Chlorinated tap water will kill the beneficial bacteria you are trying to cultivate in the tank.

When the ammonia level in the aquarium go down, start testing for nitrites and conduct water changes when necessary to keep the levels under .25 ppm.

When the ammonia and nitrite readings reach 0, the nitrogen cycle has completed and new fish can be gradually added to the aquarium. Don’t add too many fish at one time or ammonia levels will begin to spike.

After adding any new fish, it’s a good idea to test the water for a few weeks to ensure that there are no sudden ammonia spikes.

Fruit Flies (Drosophila melanogaster) mating

Fruit Flies (Drosophila melanogaster) or Vinegar Flies are often bred by tropical fish keeping enthusiasts to feed topwater species like African Butterfly Fish, Archer Fish, Hatdhetfish, Killifish, etc.

Although Fruit Flies are sold in specialty pet shops and online for feeding young praying mantis, small spiders, frogs, fish, and a variety of other small insects, you can breed them yourself and save a good bit of money.

Flightless Fruit Flies like Drosophila hydei or Drosophila melanogaster have a mutation that makes their wings underdeveloped.   Even though they still have wings, they are unable to fly.

Fruit Flies (Drosophila hydei)

Fruit Flies (Drosophila melanogaster)

The main difference between the two species is size. Drosophila melanogaster are small at about 1/16th of an inch long, whereas Drosophila hydei are meatier at about 1/8th of an inch long.

Breeding either species of Fruit Flies is easy and requires items you can find in your local supermarket.

You will need the following:

• An initial batch of Drosophila melanogaster or Drosophila hydei Fruit Flies.
• Seven or eight 10 to 20 oz. plastic containers with lids.
• Some tissue paper
• Mashed potato mix (without seasonings)
• Beer (any brand)
• White vinegar
• Dried yeast
• Some wood, plastic, or paper strips for the flies to sit upon 
  

  Fruit Fly Culture Container

First, prepare the medium for feeding the Fruit Flies:

Mix about 17 to 18 oz. of beer with 7 oz. of mashed potato mix until smooth and add about 3.5 oz of white vinegar.   The resulting mix should be smooth without being too watery.  If it is too dry, add a small amount of water; if too wet, add some more mashed potato mix.   When you’re happy with the consistency, add a tsp of dry yeast and stir well.

Next, prepare the breeding containers.

• Cut a hole in each of the container lids about the size of a half dollar.
• Take a piece of tissue paper and place it in between the lid and the container. The paper allows air into the container without letting the fruit flies escape.
• Add equal portions of the Fruit Fly medium to each of the containers. You don’t need to fill the containers up, but add just enough to cover the bottom.
• Add the wood or plastic strips into the containers on top of the medium. It should not sink into the medium. It needs to stay on top for the flies to perch on so they don’t drown.

Next, add the Fruit Flies.

Gently, shake or tap 20 to 30 Fruit Flies into each container and close the tissue paper fitted lid. Firmly tap the container so the fruit flies fall to the bottom, and set the containers in a 70° to 86° F. room for the Fruit Flies to develop.

The Fruit Flies take longer to develop at lower temperatures and should not be kept below 59 ° F.

melanogaster pupae

The initial stock of Fruit Flies will lay eggs inside the medium and after a few days, tiny maggots will appear moving around inside the medium.

In about two weeks or so, when you see the orange/brown fly pupae sticking onto the side of the container, the next generation of Fruit Flies will be only a few days away.

The smaller fruit flies (Drosophila melanogaster) develop faster than the larger ones (Drosophila hydei).

After a couple of weeks, just about when the maggots reach adulthood, the medium in the containers will be dried up.

If you haven’t fed all the Fruit Flies to your fish or praying mantis, you can still keep them alive by adding a small piece of fruit or a little more culture medium to the container.

NOTE:

Both species of flightless fruit flies are capable of regenerating their ability to fly.    Flightlessness is a recessive gene that both parents have to posses.   If a wild fruit fly that can fly introduces its DNA into the gene pool, your flightless  fruit flies will begin to “magically” fly again.   So if you don’t want to deal with a bunch of annoying little fruit flies escaping and flying all over your house, keep your cultures safe from foreign fly DNA.

Fruit Flies are a great high protein live food for a variety of tropical fish species and are readily available from a variety of sources if you don’t care to breed them yourself.

Koi_Feeding Frenzy

Koi (Cyprinus rubrofuscu) known to tropical fish keeping enthusiasts as Jinli, Nishikigoi, or Brocaded carp are brightly colored variants of the common Amur carp, which is widespread in East Asia from the Amur to the Red River drainages.

Koi (Cyprinus rubrofuscu) are native to China, Laos, and Vietnam, and were once considered a subspecies of the common European carp (Cyprinus carpio haematopterus).

Although they are different species, Koi and some Goldfish (Carassius auratus) are often misidentified by tropical fish keeping enthusiasts.   Koi and Goldfish can interbreed but because they were developed from different carp species, their offspring are sterile.

Some varieties of goldfish like Comets, Shubunkins, and common Goldfish have similar body types as juveniles; but Koi have prominent barbels on their lip, which goldfish lack.  Goldfish are also much smaller than koi, have a greater variety of fin and tail configurations, and body shapes.  Koi can grow quite large (over 3 feet in length), while goldfish max out at about 2 feet.

History:

Carp are a highly adaptable cold water species that can survive in many climates and water conditions.   Over the years domesticated carp, Koi, were propagated in many locations including China and Japan.

Prussian Carp (CarassiusGiebelio)

Carp were first selectively bred for their color in China over a thousand years ago by breeding Prussian carp (Carassius gibelio) which led to the development of various species of goldfish (Carassius auratus).

By the Song dynasty (960–1279); orange, red and white, yellow, and pure white, colors had been developed.

Amur carp (Cyprinus rubrofuscus) were aquacultured as a food fish in China during the fourth (Jin Dynasty) and fifth century with different color varieties noted.

Cyprinus rubrofuscus were first bred for their color variants in the town of Ojiya, Japan during the 1820s.    Until 1914 when Niigata koi were shown at an exposition in Tokyo, Japan, nobody was aware that color variations even existed.

Since then, the interest in Koi by the tropical fish keeping community has spread throughout the world, and from that handful of Koi, all the other Nishikigoi varieties except the Ogon, were developed.

Koi are now distinguished by their colors, patterns, fins, and scales.   The color varieties, basically black, white, red, yellow, blue, and cream, are virtually limitless.  Breeders have categorized Koi according to combinations of color, patterns, scales, fins, and quality.

Gosanke is made up of the Kohaku,Taisho Sanshoku, and Showa Sanshoku varieties.

In the 1980s, a hybrid of Ogon Koi and wild European carp developed a “Ghost Koi” that had metallic scales.   Another hybrid of Koi with Asian carp in the 1980s developed into the butterfly Koi, longfin Koi, or dragon carp.

Dragon Koi

Major Koi Varities:

• Kōhaku – isa white bodied koi with large red markings on the top.   Kōhaku means “red and white”.
• Taishō Sanshoku (or Taishō Sanke) – is similar to the kohaku, except for the addition of small black markings called sumi.
• Shōwa Sanshoku (or Showa Sanke) – is a black koi with red and white markings.
• Tanchō – is any Koi with a solitary red patch on its head.   The fish may be a Tanchō Shōwa, Tanchō Sanke, or even Tanchō Goshiki.  It is named after the Japanese red crowned crane (Grus japonensis).
• Chagoi – is a tea colored Koi.   This koi can range in color from a pale olive drab green or brown, to a copper or bronze, to more subdued shades of orange.
• Asagi – This Koi is light blue above and usually red below.   It can be a pale yellow or cream, generally below the lateral line and on the cheeks.
• Utsurimono – is a black koi with white, red, or yellow markings, in a zebra color pattern.   The black and yellow form is called Ki Utsuri. The red and white form is called Hi Utsuri.   There is also a piebald color morph called Shiro Utsuri.
• Bekko – is a white, red, or yellow skinned Koi with black markings.   The Japanese name means “tortoise shell”.   The white, red, and yellow varieties are called Shiro Bekko, Aka Bekko, and Ki Bekko, respectively.
• Goshiki – is a dark koi with red (Kōhaku style) hi pattern.  It is similar to an Asagi, with little or no hi below the lateral line and a Kōhaku Hi pattern over reticulated fishnet patterned scales.   The base color can range from almost black to a very pale, sky blue.
• Shūsui – Means “autumn green”.   It was bred in 1910 by crossing a Japanese Asagi with a German mirror carp.   Except for a single line of large mirror scales that extend dorsally from head to tail, the fish has no scales.   The most common type of Shūsui has a pale, sky-blue/gray color above the lateral line and red or orange (and very rarely bright yellow) below the lateral line and on the cheeks.
• Kinginrin – Often abbreviated to Ginrin, is a koi with glittering, metallic scales.  Their sparkling, glittering scales contrast to the smooth, even, metallic skin and scales seen in the Ogon varieties.
• Kawarimono – is a catch all category for Koi that cannot be put into one of the other categories.
• Ōgon – is a single colored metallic Koi.   Gold, platinum, and orange are the most common colors and cream colored specimens are considered rare.   The variety was created by Sawata Aoki in 1946 from wild carp he caught 25 years earlier.
• Kumonryū – is a black doitsu-scaled fish with curling white markings.
• Ochiba – is a light blue gray Koi with a copper, bronze, or yellow pattern.  The Japanese name means “fallen leaves”.
• Koromo – is a white bodied fish with a Kohaku-style pattern, and blue or black edged scales only over the hi pattern.   The most common Koromo is the Ai Goromo, which is colored like a Kohaku, except that each of the scales within the red patches has blue or black edging.
  The less common Budo-Goromo, has a darker burgundy hi overlay that gives it the appearance of bunches of grapes.
  The rarely seen Tsumi-Goromois similar to Budo-Goromo, but the hi pattern is such a dark burgundy that it appears almost black.
• Hikari-moyomono – Is a Koi with colored markings over a metallic base; or in two metallic colors.
• Kikokuryū – is a metallic skinned version of the Kumonryu.
• Kin-Kikokuryū – is a metallic skinned version of the Kumonryu with a Kohaku-style hi pattern. At least six different genetic sub-varieties of this general variety are known.
• Ghost Koi – is a hybrid of Ogon and wild carp with metallic scales.
• Butterfly Koi – is a long flowing finned hybrid between Koi and Asian carp. The colors depend on the koi stock used to cross.
• Doitsu-goi – were created by crossbreeding numerous different established Koi varieties with “scaleless” German carp; usually fish with a single line of scales along both sides of the dorsal fin.

There are four main types of Doitsu scale patterns:

• The most common type, Kawi Goi, has a row of scales along both sides of the dorsal fin that starts at the front and ends at the end of the dorsal.
• The second type has a row of scales that starts where the head meets the shoulder and runs along both sides of the entire length of the fish.
• The third type, Kagomi Goi, is the same as the second, but has a line of often quite large scales running along the lateral line along the side of the fish. This type is commonly called “Mirror Koi”.
• The fourth, Yoroi Goi, and rarest type is the “Armor Koi”.  It is almost completely covered with large scales that resemble armor plate.  It is also called Kagami-goi or mirror carp.

Koi are a hardy, peaceful, easy to maintain cold water species that are normally kept in outdoor ponds. They can tolerate swings in temperature and water quality but do not do well in areas that have extended winter temperatures.   Below 50 °F their immune systems are very weak.   Although they can tolerate less than perfect water quality, Koi do best with a good pond filtration system and skimmer to keep the water as pristine as possible.

Koi ponds in warmer climates should have a minimum depth of at least 3 feet.   In colder climates, ponds should be at a minimum, at least 5 feet deep.

Because of their bright colors, Koi enclosures should be covered to protect them from predators, especially as juveniles.   Many breeders cover their ponds with netting, wires, overhangs, etc. to prevent kingfishers, herons, raccoons, foxes, cats, etc. from feasting on their prized Koi.    An uncovered pond with juvenile yellow or white skinned Koi is a dinner bell for any kingfisher or heron in the area.

Koi are easy to breed and will to spawn on their own in a large pond during the spring and summer.   Females produce huge numbers of eggs that are fertilized by one or more males.

When ready to breed, the males will start following the female around the pond and bump or nudge her until she releases her eggs.     After her sticky eggs are fertilized by the males, they sink to the bottom and stick to the substrate until they hatch.    If the eggs can survive the first 4 to 7 days, they fry will hatch out and begin life on their own.  Females can produce several spawns, but most of the fry are eaten by other fish in the pond.

Professional Koi breeders are meticulous about selecting breeding parents based on the characteristics they want to achieve, but the fry will still exhibit a wide range of colors and quality.

From the thousands of offspring produced in a single spawning, relatively few result in show quality fish.  Based on the breeder’s expert eye, unacceptable Koi offspring are culled during various stages of development.   The culled fry are usually either destroyed or used as feeder fish.

Older culls within the first year of growth are often sold as lower grade, pond quality Koi which is what most tropical fish keeping enthusiasts purchase from local fish shops.

Koi are omnivores that eat a wide variety of foods, including worms, crustaceans, corn, peas, lettuce, and even watermelon.    Although they are bottom feeders, most nutritionally balanced commercially prepared Koi foods are designed to float on the surface so the fish can be better observed.    A few food manufactures produce combinations of mixed sinking and floating pellet food.

Hand Feeding Koi

Over time, Koi will learn to recognize the persons feeding them and will gather around them during feeding.   They can even be trained to take food from you hand.

Do not feed Koi during the winter months.   Their digestive systems slow down to a halt and they eat very little, if any food.   Stop feeding when water temperatures drop below 50 °F.

In smaller ponds, make sure that proper oxygenation and pH stabilization occurs during temperature drops in the winter months.   A good fountain pump in the center of a pond or a commercial grade bubble aerator will  provide all the oxygenation needed.

When spring returns, the appetites of the Koi will also return and normal feedings can resume.

Koi can live to 50 years and longer.  If you pamper and take care of your Koi, they can easily outlive you.   Well cared for Koi have been reported to live over 200 years.

A famous Koi named “Hanako” owned by several people lived to be 226 years old, according to the growth rings on it’s scales.

Koi are available to tropical fish keeping enthusiasts from breeders, importers, wholesalers, collectors, online, and from almost every pet shop in the world.   Prices range from just a few dollars, to literally hundreds of thousands of dollars for unique show quality specimens.

Harvesting Koi

Minimum Pond Size: 300 gallons
Care Level: Easy
Temperament: Peaceful
Aquarium Hardiness: Hardy
Water Conditions: 59-77° F, KH 2-12, pH 6.8-7.2
Max. Size: 40″
Color Form: Orange, Red, White, Black, Blue, Green
Diet: Omnivore
Compatibility:  Ponds or large tanks
Origin: China
Family: Cyprinidae
Lifespan: Up to 200 years
Aquarist Experience Level:  Beginner

Taeniolethrinops Praeorbitalis

Taeniolethrinops praeorbitalis is a peaceful, solitary cichlid endemic to Lake Malawi that is found over sandy substrates in relatively shallow depths of up to 160 feet.

Taeniolethrinops praeorbitalis can be distinguished from it’s close relative Taeniolethrinops laticeps, by it’s longer snout and the absence of an oblique dark diagonal line that crosses the upper portion of the body in adults.

Taeniolethrinops praeorbitalis

Juvenile Taeniolethrinops praeorbitalis have a bright yellow head which becomes less vivid in adult specimens.   Adult males have a blue background coloring especially during breeding, while females remain a drab silver gray color.

Although Taeniolethrinops praeorbitalis are found throughout Lake Malawi, most of the specimens collected for tropical fish keeping enthusiasts are from Senga Bay.

Taeniolethrinops praeorbitalis are a peaceful species that can be housed with other peaceful, similarly sized cichlids such as cyrtocara, copadichromis, protomelas, etc.

Taeniolethrinops praeorbitalis are best housed in an aquarium of at least 150 gallon capacity with a sandy or fine gravel substrate and some large stones strategically formed into hiding places.    Aquatic plants are not necessary and would undoubtedly be dislodged by their digging activities.   They require good filtration, regular water changes, and are good candidates for wet/dry, multiple bio-wheel, or canister filtration systems.

Taeniolethrinops praeorbitalis are maternal mouth brooders that have been farm raised for the tropical fish keeping community.   They have been bred in an aquarium environment by hobbyists using the classic methods for oral incubators.

During breeding, to attract pregnant females, the males construct large craters in the sand that often exceed three feet in diameter.   The males stay in the depression until a pregnant female is attracted and breeding takes place.   The females will incubate the eggs for about three weeks and should have several rocky hiding places available during this time to seclude herself and minimize stress from other tank mates.

In their natural environment in Lake Malawi, Taeniolethrinops praeorbitalis roam the shorelines digging deep into the sandy substrate with their long snouts looking for insect larvae, small crustaceans, and invertebrates.   They are often shadowed by C. moorii and P. annectens that take advantage of Taeniolethrinops praeorbitalis’s digging to feed on the exposed leftovers.

In an aquarium environment, they can be fed live, frozen, and freeze dried mysis shrimp, shrimp, prawns, krill, along with a quality sinking carnivore pellet.

Although Taeniolethrinops praeorbitalis are considered common, they are not readily available.  They can be purchased from specialty fish shops or online from a variety of sources, including Cichlid forums, auctions sites, importers, retailers, wholesalers and collectors at a variety of sizes.

Taeniolethrinops praeorbitalis

Minimum Tank Size: 180 gallons
Care Level: Mildly Difficult
Temperament: Peaceful
Aquarium Hardiness: Hardy
Water Conditions: 71.0 to 82.0° F, dH 6-10°dGH, pH 7.5-8.6
Max. Size: 13.5″
Color Form: Yellow, Blue, Green
Diet: Carnivore
Compatibility: Single species or peaceful Malawi
Origin: Lake Malawi
Family: Cichlidae
Lifespan: 8-10 years
Aquarist Experience Level: Advanced

Green Neon Tetra (Paracheirodon simulans)

Green Neon Tetra (Paracheirodon simulans) also known to tropical fish keeping enthusiasts as False Neon Tetras or Blue Neon Tetras are found in the border areas of the mid to upper Rio Negro drainage in Brazil upstream from the mouth of the Rio Branco, and between the mouth of the Rio Meta and San Fernando de Atabapo in the Rio Orinoco river system in the border region between Venezuela and Columbia.

The Green Neon Tetra (Paracheirodon simulans) exclusively inhabits blackwater environments like the Rio Jufaris, a tributary located just upstream of the Rio Negro in the Amazonas state of Brazil.   Their range coincides with that of the Cardinal Tetra (Paracheirodon axelrodi) but the two species are not found together.

Green Neon Tetra (Paracheirodon simulans)

The Green Neon Tetra (Paracheirodon simulans) has a brilliant blue green lateral stripe on the body that runs to the base of the caudal fin.

It differs from Neon and Cardinal Tetras by it’s smaller size, the much greener lateral stripe that covers most of the head and eye that extends to the base of the tail, and the less pronounced red patch.

The flanks are duller and appear to have less red pigmentation than either Paracheirodon innesi and Paracheirodon axelrodi.   Males are smaller and thinner than sexually mature females which are larger and have noticeably more rounded bodies.

Paracheirodon simulans live in warm, slow to moderately flowing tannin stained water over sandy substrates covered with leaf litter, fallen branches, and bogwood. The thick, overhanging bank and submerged vegetation provides cover and the dimly lit conditions found only in the upper, terra firme, reaches of tributary drainages.

These waters are typically acidic, stained a brown tea color by decomposing organic matter, and have a negligible carbonate hardness.

Although Paracheirodon sumulans are a peaceful shoaling species, they are not good candidates for a community tank.   Their small size and specialized blackwater requirements make them better suited for a single species setup or with docile characids, smaller callichthyids, and loricariids.

Green Neon Tetras are best housed in groups of 8 to 12 individuals in a densely planted tank of at least 10 gallon capacity with a sand or very fine gravel substrate and some driftwood roots and branches.   Dried leaf litter, Alder cones, Beech, or Indian Almond leaves should be added to provide cover and promote the growth of beneficial microbe colonies as decomposition occurs. The microbes also serve as a valuable food source for the fry.

Because Green Neon Tetras do best under low light conditions; floating plants like Ceratopteris spp. and plants that thrive in dimly lit conditions like Microsorum, Taxiphyllum, or Cryptocoryne spp. should be added to the tank to provide cover and shade.

Paracheirodon sumulans are extremely sensitive to fluctuations and deterioration of water quality and should only be added to mature aquariums.

Paracheirodon simulans have not be bred in an aquarium environment.

In their natural habitat, Green Neon Tetras feed on algae, insects, small inverts, and crustaceans.   In an aquarium environment they do well on a varied menu of quality flake food combined with live, frozen, or freeze dried bloodworms, Daphnia, mosquito larvae, Moina, etc.

True Green Neon Tetras (Paracheirodon simulans) are wild caught specimens. They have not been bred on a commercial basis which makes them less common and more expensive than their congeners.   Tropical fish keeping enthusiasts can occasionally purchase them from specialty fish shops, online from importers and auctions sites, or on tropical fish forums.

Green Neon Tetra (Paracheirodon simulans)

Minimum Tank Size: 10 gallons
Care Level: Easy
Temperament: Peaceful
Aquarium Hardiness: Hardy when acclimated
Water Conditions: 77-95° F, H 18-143, pH 3.0-6.5
Max. Size: .6 – .98″
Color: Iridescent Green, Red
Diet: Omnivore
Compatibility: Peaceful
Origin: Brazil
Family: Characidae
Lifespan: 5 – 8years
Aquarist Experience Level: Advanced

Head and Tail Light Tetra (Hemigrammus ocellifer)

The Head and Tail Light Tetra (Hemigrammus ocellifer) known to tropical fish keeping enthusiasts as the Beacon Fish originates in South America in the Amazon and Orinoco River basins, parts of Guyana, Suriname, French Guiana, Peru and Brazil.   Because of its popularity with tropical fish keeping enthusiasts worldwide, they are bred in huge numbers for the aquarium trade.

Head and Tail Light Tetras are a peaceful shoaling species that prefer slow moving rivers, streams, and floodplain lakes.

Head and Tail Light Tetra (Hemigrammus ocellifer)

The Head and Tail Light Tetra’s body is compressed, oval in shape, and an iridescent silver color.   The rear part of the body and fins are almost translucent. It gets its common name from the two reflective black spots surrounded by copper coloring at the base of the tail and next to the gill cover that resemble auto headlights.

A fine black line starting mid body runs to the black spot at the base of the caudal fin. The upper part of their black and yellow eye is ringed in red and looks similar to Redeye Tetras.

Adult males when viewed from above are smaller and thinner than females. Females are generally larger and more heavily bodied than males. They can be sexed by examination of the swim bladder, that is visible through the translucent skin. In males the swim bladder tapers to a point. In females, it is more rounded.

A similar but more slender species, Hemigrammus ocellifer falsus, has the taillight spot, but lacks the second spot behind the gill cover.

Head and Tail Light Tetras do best in schools of 6 or more individuals and can be housed with other peaceful tetras, barbs, danios, rasboras, and several other small to medium sized fish in a community tank environment.   Small loaches, catfish, dwarf cichlids, and dwarf gourami are also suitable tank mates but avoid large fish and slow moving, long finned species like bettas and angelfish.

The Head and Tail Light Tetra is a perfect candidate for a black water biotope setup.   They are best housed as a shoal of 10 or more of their own kind in a planted tank of at least 20 gallons with a river sand or fine gravel substrate, some driftwood branches and some dried Indian Almond, Beech, or Oak leaves to replicate their natural waters. A peat bag added to the filtration system can be substituted to simulate the weak tea colored conditions that they are found in.

Some small floating plants like duckweed, can be added to provide shady spots, diffuse overhead lighting and mimic the dimly lit conditions they prefer. Frequent water changes are recommended.

Be sure to replace the dried leaves every couple of weeks, so as not to foul the aquarium water.

Head and Tail Light Tetras are relatively easy to breed in an aquarium.

Set up a breeding tank with plenty of fine leaved plants for them to lay their eggs, dim lighting, and soft, slightly acidic water. A temperature of 80 degrees F, a pH of 6.0 to 6.5, and a gH of 1-5 will do the job.

Condition several specimens with live or frozen brine shrimp,bloodworms, daphnia, etc. for a week or two, select a ripe female and the best colored male, and place them in the breeding tank.   The female’s belly will swell with eggs when spawning is imminent and usually occurs in the morning hours.   Over the course of a day, up to 1,000 eggs will be laid on the plants.

When spawning is over, promptly remove the parents from the tank.   The eggs hatch in about 24 hours and the fry are free swimming in a couple of days.   When the egg sacs are absorbed, they can be fed Infusoria, commercially prepared powdered fry food, egg yolk, etc. until they grow large enough to accept newly hatched brine shrimp or mircoworms.   Because the eggs and fry are light sensitive in the early stages of life, keep the rearing tank in complete darkness if at all possible.

Head and Tail Light Tetras are omnivorous and in an aquarium environment will readily accept just about anything offered.   Regular meals of live, frozen or freeze dried brine shrimp, bloodworms, small insects, and Daphnia, along with a quality dried flake food or granule will keep them in the best condition.

Head and Tail Light Tetras, also known as Beacon Tetras, are common in most tropical fish shops. It is popular, hardy, inexpensive, and one of the best choices for newcomers to tropical fish keeping. Selectively bred albino specimens have become popular in recent years and are readily available.

Head and Tail Light Tetra (Hemigrammus ocellifer)

Minimum Tank Size: 20 gallons
Care Level: Moderate
Temperament: Peaceful
Aquarium Hardiness: Hardy
Water Conditions: 74 to 82 °F , dH 5-20, pH 5.5-7.5
Max. Size: 1.8″
Color Form: Silver, Black
Diet: Omnivore
Compatibility: Peaceful, keep with other small tetras
Origin: Amazon and Orinoco River basins
Family: Characidae
Lifespan: 5 years
Aquarist Experience Level: Beginner

Green Neon (Hemigrammus hyanuary)

The Green Neon (Hemigrammus hyanuary) known to tropical fish keeping enthusiasts as the January Tetra or Costello Tetra is found in the Amazon River basin in Brazil and Peru; specifically Lake Hyanuary near Manuas, Brazil.

Green Neons are an active shoaling species that are found in the black waters of slow moving rivers, river tributaries and seasonally, the floodplains of lakes.

Green Neon (Hemigrammus hyanuary)

The Green Neon has a silver to olive green body with a yellow to green iridescent stripe that extends from the snout to the base of its caudal fin. A black band below the stripe extends from the tail to mid way on the body.   It has transparent fins and a silver to orange colored patch directly above the stripe at the base of the tail.

Although they are often confused with the more common head and tail light tetra, H. ocellifer; adult Green Neon tetras have a bright green colored iris.

Adult male Hemigrammus hyanuary have a small hook on the anal fin and are a bit smaller and noticeably slimmer than females.

Green Neon tetras are perfect candidates for a blackwater biotope setup with at least 6 or more of their own kind.  They are best housed in at least a 10 gallon tank with a sandy or very fine substrate, some driftwood branches, and some dried Indian Almond, Beech, or Oak leaves to replicate their natural waters.  Submerged plants are optional.  A peat bag added to the filtration system can alternately be used to simulate the weak tea colored waters that they are found in.

Some small floating plants like duckweed, can be added to diffuse overhead lighting and mimic the dimly lit conditions they prefer.   Frequent water changes are recommended.

Be sure to replace the dried leaves every couple of weeks, so they don’t foul the aquarium water.

Green Neon tetras can be housed in a community tank environment with other small, peaceful, South American species. Suitable candidates are other species of Hemigrammus or Hyphessobrycon, pencil fish, smaller rasboras, barbs, dwarf Apistogramma or Pelvicachromis species cichlids, Corydoras, and small Loricariids.

Green Neon tetras are often bred in an aquarium environment similar to other tetra species.

Set up a small, dimly lit breeding tank with spawning mops or fine leaved plants like Java Moss to give the fish a place to deposit their eggs and a small air powered sponge filter. The water needs to be at a pH of 6.0, 4 dH, and a temperature from 79-84°F. Peat bags or Indian Almond leaves can be used but are not necessary.

Green Neons can be spawned in groups or in pairs.

Place 5 or 6 pairs of Green Neons that have been conditioned with feedings of small live foods into a breeding tank and let nature take over.   The fish will spawn in the early morning hours.

When breeding pairs, condition several fish and select the fattest egg filled female and a male that displays the best color and place them in the breeding tank during the evening.   The pair should spawn early the next morning.

Both parents will eat their eggs when given the chance and should be removed from the breeding tank as soon as the eggs are observed.   The eggs will hatch out in 24 to 36 hours and the fry becoming free swimming a 3 to 4 days later.

For the first few days, the fry should be fed infusoria until they grow large enough to accept baby brine shrimp, microworms, finely crushed flake food, etc. Because the fry are light sensitive, keep the rearing tank dark during the first few weeks of growth.

Professional breeders cover the bottom of a bare tank with a fine mesh large enough for the eggs to pass through, yet small enough so the adults cannot reach them.

In their natural habitat, Green Neons (Hemigrammus hyanuary) feed on small invertebrates.   In an aquarium environment, they are not fussy eaters and should be fed a balanced diet of dried flake food with live, frozen, or freeze dried aquatic insects, brine shrimp, daphnia, bloodworms, Tubifex, etc.

Most Green Neons (Hemigrammus hyanuary) available to tropical fish keeping enthusiasts are captive bred in Singapore Malaysia. They are occasionally available for purchase from specialty fish shops and online from a variety of sites when they are 3/4″ to 1-1/2″ in size.

When kept in alkaline conditions, Green Neons will lose their coloration.

Green Neon (Hemigrammus hyanuary)

Minimum Tank Size: 10 gallons
Care Level: Moderate
Temperament: Peaceful
Aquarium Hardiness: Hardy once acclimated
Water Conditions: 74 to 82 °F , dH 6-15, pH 6.0-7.5
Max. Size: 1.6″
Color Form: Silver, Yellow, Green
Diet: Omnivore
Compatibility: Peaceful, keep with other small tetras
Origin: Lake Hyanuary, Farm Raised in Singapore
Family: Characidae
Lifespan: 5 years
Aquarist Experience Level: Beginner

Giant Raphael Catfish (Megalodoras uranoscopus)

The Giant Raphael Catfish (Megalodoras uranoscopus) also known to tropical fish keeping enthusiasts as the Giant Talking Catfish, Mother of Snails Catfish, Megalodoras Catfish, or Ripsaw Catfish, is a native to the Amazon River Basin in Bolivia, Brazil, Colombia, Ecuador and Peru.

Giant Raphael Catfish (Megalodoras uranoscopus) have been recorded in the Amazon, Essequibo, and Tocantins river systems and grow to a length of 28 inches or more.

Giant Raphael Catfish prefer slower moving creeks, swamps, river tributaries, and areas like Lake Hyanuary, close to the rainforest city of Manaus, Brazil, They are usually found hiding among tree roots and submerged vegetation but depending on the time of year, they can also be found in temporarily flooded areas and in the main river channels.

Although Giant Raphael Catfish occasionally form small schools, they prefer living in smaller groups. In the wild they feed on Licania longipetala and Astorcaryum jauari palm fruits and are particularly fond of pulmonate snails.

Giant Raphael Catfish (Megalodoras uranoscopus)

Although Giant Raphael Catfish have an attractive color pattern that remains with age, they are rarely imported for the aquarium trade. In their native range, they are a commercially harvested as a food fish.

Megalodoras uranoscopus is known for its ability to produce sounds by locking their spiny pectoral fins into their sockets, grinding them against the inner portion of the socket and resonating their swim bladder using a muscle in the back of their skull to produce a deep clicking sound.

Because of their large size, a single Giant Raphael Catfish should be housed in an aquarium with minimum dimensions of 4′ X 8′ with a bare or sandy substrate and large pieces of driftwood or a length of large diameter PVC pipe for them to hide.   They are a shoaling diurnal species that require dim lighting and because of the copious amounts of waste they produce, a large, efficient, filtration system.   High end canister filters or wet/dry filters are a must for this species in order to maintain good water quality.

Giant Raphael Catfish are peaceful and do best when housed in groups of 4 or more specimens.  They can be maintained in a large community aquarium with like sized doradids like Pseudodoras niger, Potamotrygon, Osteoglossum spp., larger loricariids, Rays, or characids like Myleus or Metynnis spp.

Megalodoras uranoscopus are easily sexed but have not been bred in an aquarium environment.

In their natural habitat, Giant Raphael Catfish eat snails and palm fruits that drop into the water.  In an aquarium environment, they are not fussy eaters and will scavenge food from the bottom, but in order to maintain a healthy immune system, they need both meaty and plant based foods in their diet.

Commercially prepared sinking catfish pellets, earthworms, frozen bloodworms, prawns, snails, blanched vegetables, and vegetable wafer type foods will keep them healthy.

It’s best to feed them only 2 to 4 times a week and increase the amount and frequency as the fish grow.   As the fish settle into their environment they will come to the surface to accept food.

Giant Raphael Catfish (Megalodoras uranoscopus) are occasionally available from importers online and specialty tropical fish shops in the United States as juveniles. Prices vary according to demand.

Giant Raphael Catfish (Megalodoras uranoscopus)

Minimum Tank Size: 180 gallons
Care Level: Moderate
Temperament: Peaceful
Aquarium Hardiness: Hardy
Water Conditions: 70-79° F, KH 0-25, pH 5.5-7.5
Max. Size: 28″
Color Form: Brown, Black, White, Gold
Diet: Omnivore
Compatibility: Good community tank fish
Origin: Brazil, Peru, Columbia, Bolivia
Family: Doradidae
Live Span: 5 to 20 years
Aquarist Experience Level: Experienced

Gill Fluke (Dactylogyrus)

Gill Flukes (Dactylogyrus) and Skin Flukes (Gyrodactylus) are common parasitic flatworms that affect fish, frogs, and turtles.   Despite their names, both Trematoda can be found on the skin and gills of cold water and tropical fish where in small numbers do little harm to healthy fish.   In large numbers, Flukes (Trematoda) are debilitating and often the cause of secondary bacterial infections.

There are over 10,000 species of Trematoda that occur worldwide.   They range in size from about 0.2 inches to 4 inches in length and infect domestic animals, humans, mollusks, and crustaceans in addition to almost all tropical fish.   Flukes can attach themselves externally, internally (in the gut), and semi externally in the gills and mouth of fish.

The Gill Fluke (Dactylogyrus) uses hooks on it’s body to attach itself to the flesh of the fish’s gills.   As it multiplies, it reduces the ability of the fish to take in oxygen, the fish becomes listless and dies of oxygen starvation or from a bacteria infection.

Gill Flukes (Dactylogyrus) live for about a week and drop eggs which hatch out with 2 to 4 days. The larvae die without a host in about…..

PHYSICAL SYMPTOMS:

Gill Flukes and Skin Flukes are small, flat, white, worm like parasites that are difficult to spot without the aid of a microscope.

Symptoms include the following:

Gill Fluke (Dactylogyrus)

Gill Fluke (Dactylogyrus):       

Loss of appetite
Fish becomes lethargic
Irritated, discolored, sloppy looking gills
Gasping at the surface

Skin Fluke (Gyrodactylus)

Skin Fluke (Gyrodactylus):

Rubbing and flashing
Tiny red spots or yellow dusting
Sores and ulcers
Clamped fins
Changes in the slime coat

In the more advanced stage of Gyrodactylus infestations, the fish become lethargic and will spend long periods on the bottom of the tank isolating itself with it’s fins clamped close to the body.

In the advanced stage of Dactylogyrus infestations, fish will often display swollen, discolored gills, and have no appetite.    The gill covers may be clamped shut or remain wide open and the skin of the fish can be cloudy due to the excess amount of mucus being produced.

Severely infected fish will usually be gasping for air at the surface where the water has a higher concentration of oxygen, or laying at the bottom suffering from severe gill damage.

Severe infestations will kill fish directly or by secondary infections.

CAUSE:

Flukes (Trematoda) are caused by introducing infected fish or plants that carry the eggs of the parasite, or the adult parasite into a pond or aquarium.

TREATMENT:

Of the numerous Fluke treatments that are available to treat both live bearing and egg laying Trematatoda, those containing Praziquantel are the most effective.

Most Fluke treatments target the juvenile and adult stage which is satisfactory for Gyrodactylus, but for Gill Flukes (Dactylogyrus) and other egg laying Trematoda, several treatments are required over a period of several weeks to kill off the offspring of the hardy eggs.    There is no fish safe treatment that will kill fluke eggs, which is why re-treatments are necessary to completely break the life cycle.

When there are large amounts of dissolved organic matter in the pond or aquarium water, repeated treatments after 7 days are definitely required.

Most tropical fish keeping enthusiasts use Praziquantel (prazi) as a safe, effective, “go to” treatment for Skin Flukes (Gyrodactylus sp.), Gill Flukes (Dactylogyrus sp.), and tapeworms in Koi, goldfish, and tropical fish.   Although Praziquantel is primarily used to treat parasitic worm infections in humans and animals; it is also used in ponds, aquaculture, and aquariums.

Praziquantel, or prazi, is gentle on fish, safe to use with aquatic plants, and will not affect the biological filtration in your aquarium or pond.

Praziquantel is a white powder that is notoriously hard to dissolve in water, and the liquid form of prazi will often precipitate out of solution on the bottom of the container.   It is sold by a variety of sources i.e. Pet Mountain, PondRx, Drs Foster and Smith, and others.

Tropical fish keeping enthusiasts have come up with a simple trick to dissolve prazi using a nylon stocking or bit of pantyhose.   Just put the required dose in the stocking, tie it off, submerge it in the pond or aquarium, and gently roll it between your fingers until it all disperses.  The dissolved prazi will immediately come out of the stocking and look like a white cloud as it is dispersed into the tank or pond water.

For pond applications:

• Remove all carbon from the pond filter
• Turn off the ultraviolet sterilizer
• Dose at a rate of 1 gram per 100 gallons of pond water for prolonged treatment.
• Reapply after 4 or 5 days if needed
• A partial water change can be made a week after the last application but is not required.

For live bearing Skin Flukes, one treatment is usually enough to kill both adult and juveniles.  With extremely heavy infestations, a second treatment is suggested.

For egg bearing Gill Flukes, two treatments spaced 4 or 5 days apart are necessary.   The first treatment kills the adults and juveniles, but not the eggs.   The second followup treatment 5 days later will kill the newly hatched eggs.

For aquarium applications:

Fish Tapes from Thomas Labs is Praziquantel in 34 mg tablets or loose powder form.

Capsules:

• After vacuuming the tank and making a water change, distribute the contents of one 34 mg capsule into the aquarium for every 4 gallons of water.
• Remove all activated carbon and discontinue UV sterilization, but do not stop filtration.
• One 5 to 7 day treatment is generally sufficient.
• Do not apply more than once every 3 to 5 days.
• Do not mix with any other drugs.

Loose Powder:

• For every 4 gallons of aquarium water, evenly distribute 1 level tsp of Praziquantel powder around the perimeter of the tank or directly into the filter.
• Remove all activated carbon and discontinue UV sterilization, but do not stop filtration.
• One 5 to 7 day treatment is generally sufficient.
• Do not apply more than once every 3 to 5 days.
• Do not mix with any other drugs.

After the Flukes are eradicated, treat the tank with a general bacteria cure.

PREVENTION:

Poor water quality and warm temperatures accelerate the reproductive cycle of Flukes (Trematoda), and because the life cycle of monogenean Flukes do not require an intermediate host, they can remain in a closed aquarium environment almost indefinitely.

The best prevention for Fluke infestations is to quarantine all fish and plants before introducing them into your pond or aquarium.   Because Flukes are microscopic and difficult to detect visually, new additions to your system should be watched carefully.

Maintaining pristine water quality and controlling the waste levels in the system is important in reducing existing Fluke populations and to ensure that the fish maintain a healthy immune system.

Manage Fluke infestations with Prazinaqantel, mebendazole, toltrazuril, formalin, organophosphates, or with salt (or freshwater for marine fish) baths.

Neon Tetra Disease (Plistophora hyphessobryconis)

Neon Tetra Disease (Plistophora hyphessobryconis) is a sporozoan parasite that infects neon tetras, cardinals, rasboras, angelfish, zebrafish, and other similar species. Regardless of what you have heard, there is NO CURE for Neon Tetra Disease.

A bacterial disease that infects Neon tetras, cardinals, etc. with almost identical symptoms is often misdiagnosed as Plistophora hyphessobryconis and can be cured with antibiotics, which is why some tropical fish keeping enthusiasts believe there is a cure for the disease.

PHYSICAL SYMPTOMS:

Fish infected with Neon Tetra Disease will appear restless, break off from the school, swim erratically, exhibit localized loss of color in a small area of the body, begin to waste away, and ultimately develop a kinked spine making it unable to swim normally.

Neon Tetra Disease (Plistophora hyphessobryconis)

The first sign of Neon Tetra Disease is a small patch of color loss on the body of the fish.   Neon’s colors normally fade at night and this is normal, but when only one spot on the fish is faded or colored white and the rest of the fish’s color pattern is normal, the fish is likely infected. When the fish no longer swims or interacts with the school, the disease has already begun to affect the fish.   Fish with these symptoms never recover.

CAUSE:

Neon Tetra disease is caused by the microsporidian parasite Pleistophora hyphessobryconis which infects the skeletal musculature causing muscle tissue damage which appears necrotic and white or marbled.

The disease is quickly transmitted through all fish in the aquarium once the fish consume the dead bodies of other infected fish in the tank or live foods like Tubifex or bloodworms, which act as a carrier of the disease.

Once the other fish in the tank eat particles of the dead fish or tubifex, the microsporidian spores enter the body of the fish and begin to consume the healthy fish.

The cysts begin to show up as a pale white color on the infected fish as the fish begins to deteriorate from the inside out.

Once you see symptoms on the fish, the fish is doomed and cannot recover.

TREATMENT:

There is currently no known treatment for Neon Tetra Disease (Plistophora hyphessobryconis).

Because there are a few bacterial diseases that have similar symptoms, many tropical fish keeping enthusiasts opt to remove infected fish from the tank and try anti bacterial treatments in a hospital tank with the hope that the infection is a similar bacterial infection.

If the fish recovers, it did not have neon tetra disease but a bacterial infection.

Euthanasia is generally the most prudent option as soon as Neon Tetra Disease symptoms are observed on an individual in the tank.

PREVENTION:

The only way to prevent the spread of Neon Tetra Disease is to remove any fish showing symptoms as soon as possible and euthanize it before the disease can be passed on to other fish in the aquarium.

The agent that causes Neon Tetra Disease can live for several months in an aquarium without a host.   Any fish that can be infected by the disease should not be returned to the tank that had the disease for at least six months to prevent reinfection.

Neon Tetra Disease (Plistophora hyphessobryconis) is an extremely difficult disease to control.

Hole In The Head (hexamita) Discus

Hole In The Head (hexamita) is a protozoan parasitic infection that appears as lesions on the head and flanks of freshwater and marine fish.   The lesions are caused by Hexamita parasites that migrate into the sensory pores on the head of the fish where they cause the surrounding tissue to decay.   Because of the large amount of damage to the epidermis, secondary infections often set in making things worse.

PHYSICAL SYMPTOMS:

Other than the obvious “hole in the head”, additional symptoms include the following:

• Listlessness, restlessness
  

  Hole In The Head (hexamita)

• Emaciation, weight loss
• Darkened body color
• Pale or reddish looking patches on the skin
• Copious amounts of stringy pale white feces
• White slime discharge caused by irritation of the intestine wall
• Pitting and erosion of skin and muscle tissue around the face and body

CAUSE:

The Hexamita parasite is present in low levels in the intestines of many aquarium fish where they present no problems, however, when the immune system of a fish is weakened in some way, the parasite begins to rapidly multiply and spread to the other internal organs causing the fish to die.

Poor water quality, inadequate diet, and poor aquarium maintenance are the primary cause associated with Hole In The Head disease.

TREATMENT:

The premiere medication used to treat hexamitiasis is metronidazole; known by the trade names General Cure Freshwater & Saltwater Aquarium Parasitic Fish Disease Treatment By API, Fish Zole™ from Thomas Labs, MetroPlex™ from Seachem, Flagyl, etc.

In early stages of the infection where the fish is still eating, the most effective approach is to feed medicated fish food infused with metronidazole.   Mix 1 gram with 100 grams of food and feed the mixture for 4 or 5 days.

When the fish is not eating, add the medication directly to the tank water at a dosage of 250 mg per 10 gallons, once a day, for at least three days. After three days make at least a 50% water change with carbon filtration for a minimum of 24 to 48 hours, or perform a complete water change. Metronidazole can cause damage to the kidneys and other internal organs over extended periods and must be removed from the tank water.

Dimetridazole is also used by some tropical fish keeping enthusiasts to a lesser degree with less satisfactory results.

After the medication has been removed from the tank, improvements to water quality and diet are absolutely essential.

PREVENTION:

Hole In The Head disease (hexamita) is an accumulation of poor water quality, an unbalanced diet, and the parasite itself. To prevent the occurrence, maintain the following:

• Pristine water conditions by performing frequent, regular, water changes
• Avoid abrupt fluctuations in water temperature
• Avoid introducing new fish without first quarantining them
• A varied, balanced diet with occasional live foods

Fish Louse (Argulus spp.) On Koi

The Fish Louse (Argulus spp.) is a branchiuran (crustacean like) parasite related to crabs, shrimp, and lobsters that infest and cause disease in fresh and saltwater fish.

There are over 100 different species of Argulus distributed worldwide that infest freshwater and saltwater fish species.

Argulus foliaceus, Argulus japonicus, and Argulus coregoni are commonly found in freshwater systems where they infect Koi, goldfish, and other cyprinids as well as salmonids and centrarchids.

Fish Louse (Argulus spp.)

The Fish Louse viewed from the top has an oval to round flattened body covered by a wide carapace that is approximately 3–7 mm long, and 2–4 mm wide.   It has two compound eyes, and a thin needle like proboscis in front of the mouth tube that is used for piercing the host fish and sucking out it’s body fluids.

Adults have two prominent suckers that develop from hook like structures in juveniles, that are located on each side of the mouth and are used to attach to the fish.   They have 4 pairs of thoracic legs with small hooks and spines to help them move around on the host fish.

Females are larger than males and can be identified by the short, paired structures at their back end called seminal receptacles, that receive sperm from the male.

Adult Argulus sp. have eye spots and round suckers on the “head” end, and spermatheca on the posterior end.

LIFE CYCLE:

Argulus spp. have a life cycle that requires a single host, and unlike the non parasitic male anchorworm (Lernaea), both sexes and all stages of Argulus are parasitic.   Most Argulus have distinct male and female forms with visible testes on the males and small spermathecae on the rear of the females.   After mating, which occurs on the body of the host fish, the female detaches and lays 1 to 9 strings of up to 225 gelatinous eggs in several rows on any hard substrate or vegetation in the pond or aquarium.   After laying her eggs, the female returns to the host fish.

At a temperature of 95° F., the eggs hatch in about 10 days; at a temperature of 60° F, it can take as long as two months for them to hatch. The newly hatched larvae must find a host to attach themselves to quickly, and can only live on their yolk sacs for a couple of days.   Juvenile Argulus propel themselves through the water column using their 4 pairs of legs and then attach to a host using the claws on their short antennae.   Adult Argulus lack these claws but use a pair of suckers (maxillules) to attach.   Adult fish lice can survive without a host fish for about 2 weeks.

The entire live cycle of most Argulus species on the host fish takes anywhere from 30 to 100 days, depending on water temperature.

PHYSICAL SYMPTOMS:

Fish Louse infections may be indicated by some or all of the following:

• Flashing or rubbing against hard surfaces or substrate
• Reduced or complete loss of appetite
• Erratic swimming
• Lethargic swimming
• Hanging at to surface
• Pinpoint hemorrhages
• Anemia
• Fin and scale loss
• Increased mucus production
• Poor body condition

In some cases, there may be no obvious signs of disease other than presence of the parasite.  Adult and later stages of Argulus can be easily seen with the naked eye on the fish and swimming in the water column.  When infected fish are removed from the water, adult Fish Louse will quickly scurry off the fish back into the water.

CAUSE:

The introduction of new fish and/or aquatic vegetation into an aquarium or pond without being properly quarantined is the main cause of Fish Louse infestations.    Fish infested with juvenile Fish Lice on their skin will rapidly spread the parasite throughout an aquarium or pond if not treated.

TREATMENT:

Argulus spp. is easily treated with Microbe-Lift or DTHP.

DTHP is an organophosphate insecticide that is sold under a number of trade names like Dipterex, Dylox, D50, Masoten, Trichlorofon, Foschlor, and Neguvon.    When correct dosages and application intervals are used, it is a safe, cheap, useful cure for visible external parasitic crustaceans like Fish Lice (Argulus) and Anchorworm (Lernaea) as well as some Protozoans and flukes.

• Dipterex (Trichlorphon) is a water soluble insecticide that is often used at 98% potency to kill Argulus and Anchor Worm infestations in ponds.    A 1 milliliter to 790 – 1320 gallons of water dose used three times at 7 day intervals to treat large ponds is extremely effective.

Because Dipterex breaks down after a few days, the Argulus and Anchor Worm eggs and emerging parasites that survive the initial treatment  are killed by the follow up treatments, hence the 7 day interval treatments.

• Microbe-Lift is a safer, more convenient medication  that is safe for use on all ornamental pond fish, reptiles, amphibians and mollusks. It must NOT be used with crayfish and other crustaceans.

Using any of the above treatments may require follow up treatments for bacterial and fungal infections caused by damage to affected tissue from burrowing Fish Lice or Anchor Worms.

PREVENTION:

Prophylactic dipping and quarantining of new fish before introducing them into an existing system is the surest way to prevent Argulus infestations for occurring, especially with high risk species like Koi and goldfish.   Visual screening for adult Argulus  with extended monitoring of quarantined fish is a good alternative.

When parasites are detected, treat immediately with one of the above methods and maintain high water quality.

Sterilize the aquarium or pond completely to minimize any re infestations.

Velvet Disease (Oodinium pillularis)

Velvet Disease (Oodinium pillularis) known to tropical fish keeping enthusiasts as Gold Dust, Coral, or Rust Disease is caused by a protozoan that has a life cycle similar to Ichthyophthiriasis multifiliis (white spot disease).   Velvet is actually a round or pear shaped dinoflagellate that attacks both freshwater and marine tropical fish and can cause death when not treated promptly.

The parasite usually attacks the gills of the fish first before moving to the rest of the body and fins.   When it appears on the head, fins, and body of the fish as small, yellowish spots that give it a “dusty” appearance, the infestation is already severe.   Infected fish usually exhibit a dusty, brownish gold color.

Different Oodinium species include: pillularis, cyprinodontum, limmeticum, and ocellatum.   Oodinium ocellatum is particular to marine fish.

LIFE CYCLE:

Although Velvet  Disease (Oodinium pillularis) is similar to White Spot Disease (Ichthyophthiriasis multifiliis) and has a similar life cycle; Oodinium pillularis is a flagellate, and Ichthyophthiriasis multifiliis is a ciliate.

Velvet Disease (Oodinium pillularis) has a life cycle that is temperature dependent, typically 6 to 12 days long however, at lower temperatures it can be as long as 28 days.

The motile Oodinium dinospore swims around the water column looking for a suitable host fish species to attach itself to.

When it finds a host, it attaches itself by rooting into the skin or gills of the fish where it forms a hard shell (cyst) that protects it while it absorbs nutrients from the fish.

In this Trophont cyst stage, which is the only stage that you can actually see Oodinium pillularis on the fish, it continues growing and dividing until it looks like a fine dust covering the skin.

After a few days on the fish, the Oodinium pillularis cyst detach themselves and fall to the bottom where after a 3 to 28 day incubation period they begin to divide free into a new generation of dinospores.

During the incubation period on the bottom of the tank, a protective shell forms on the inside, which allows the reproduction by cellular division of more than three hundred dinospores.

The free swimming dinospores are vulnerable and must attach themselves to a new host within 48 hours or so or they will die.

PHYSICAL SYMPTOMS:

Velvet disease symptoms vary according to the severity of the infection.

Velvet Disease (Oodinium pillularis)

During initial stages of the infection, the affected fish will show some behavioral changes like fin twitching, rapid respiration, appetite loss, clamped fins, flashing or body rubbing.

The “flashing” behavior or scraping on the substrate is simply the fish trying to rid itself of the parasite.

As the Velvet parasite multiplies and the disease advances, the eyes become clouded, the fins are peppered, and the body looks like it has been dusted with gray to yellow colored powdered sugar.  The reason the skin of the sick fish becomes dusty and opaque is due to the excess amount of mucus that their immune system generates as a defense mechanism.

The faded, velvety looking body areas if left untreated, will slough off the protective slime coating of the fish and eventually cause death.

Velvet Disease (Oodinium pillularis)

Because the Oodinium parasite affects the gills, respiratory failures are common occurrences, and when the gills are severely damaged, death can occur in as little as 12 hours.

When condition becomes severe, the fish may exhibit the following:

• Opaque eyes
• Protrusion of the eyeballs
• Fins against the body
• Ulcers in the skin
• Skin detachment
• Pathological Physiology

CAUSE:

The most common cause of Velvet disease is poor aquarium maintenance and not quarantining new fish.   The following can also attribute to the disease:

• Sudden changes in water temperature
• Introduction of infected fish without quarantining
• Introducing tired fish that are lacking in defenses into a tank
• Old dirty water.  You should perform frequent water changes in your tanks.
• Introduction of infected plants

TREATMENT:

Because Velvet is highly contagious and usually in it’s advanced stage before being diagnosed, treatment should begin as soon as possible.  All treatment regimens are targeted at the free swimming (tomite) stage of the parasite.

TREATMENT – FRESHWATER:

• Increase the water temperature
  Raising the temperature in the tank to 82 degrees F or higher will speed up the life cycle of Oodinium and treat the infestation faster.
• Add aquarium salt to the tank
  Adding salt to the water at a rate of 1 to 3 level teaspoons per gallon increases the mucus production of the fish, reduces the osmotic stress, and helps ward off the parasite.
• Dim the lights for several days
  Because Oodinium is light dependent, dimming the aquarium lights helps to eliminate the degree of infestation.
• Treat the system with copper sulfate for ten days
  Copper sulfate is the treatment of choice for Velvet disease.   Follow the manufacturer’s instructions and treat the aquarium for a full ten days to ensure that the parasite is completely eradicated.
• Atabrine (quinacrine hydrochloride) is another effective medication that is often used to treat Velvet.
• Discontinue carbon filtration during treatment
  Because activated carbon removes drugs from the water, remove all activated carbon or charcoal from the tank being treated.

TREATMENT – SALTWATER:

• Because the Velvet parasite has semipermeable membranes and cannot control osmosis, an immediate drop in salinity can effectively control Oodinium in saltwater environments.   The Oodinium ocellatum parasite begins to absorb water as the cells try to equalize osmotic pressure with the sudden change and most strains will pop like a balloon as they fill with too much water.
• Fish and several other sea creatures can withstand and adjust to this change in osmotic pressure, but protozoan (White Spot and Clownfish Disease), dinoflagellate (Velvet or Coral Fish Disease), and flatworm (Black Spot Disease) organisms cannot.
• Monitored hyposalinity (1.010-1.013) in fish only tanks will enhance the effectiveness of most treatments.   Hyposalinity should NEVER be used in reef systems. It will kill corals and inverts.
• Repeated 10 to 15 minute fresh water baths medicated with quick cure or formalin will cause the trophants on the infected fish to dislodge themselves. Make sure to net the fish from the tank quickly or the stress of handling can do more damage than the cure.
• Like the Ick parasite, raising the water temperature will increase the reproduction rate of Oodinium, shorten the life cycle, and decrease the treatment time, however, the metabolic rate of the fish and their demand for oxygen also increases. Add several air stones to the tank being treated.
• Cupramine (copper sulfate) treatments are a very effective treatment for Velvet disease.   Treat the fish for 20 to 30 days.
• Chloroquine phosphate treatments are also used to successfully treat Velvet disease.
• Rally and Hypercure are “reef safe” medications that are considerably weaker, but are reported to work well.
• Anti-parasitic foods and garlic additives to the fish food will also help if the fish is eating.   Garlic infused foods improve the appetite of marine and freshwater fish.

PREVENTION:

Because most medications for the Oodinium flagellate will kill coral and live rock, prevention is the best treatment for Velvet disease, especially in reef tanks.

Velvet disease is a common occurrence in aquariums with poor maintenance.   Avoid the following:

• Abrupt fluctuations in water temperature
• Introducing new fish without quarantining them
• Keeping old water in the tank. Maintain frequent, regular water changes.
• Introducing marine plants with cysts. When bringing in new plants, make sure to isolate and disinfect them if possible prior to introduction.

Having the right equipment to house your fish in a pristine marine environment prevents most marine diseases.

Buy a good filtration system, protein skimmer, and UV sterilizer; quarantine all new fish, feed them a varied nutritious diet and the chance of getting Oodinium ocellatum is virtually nil.

Because Velvet disease can happen so quickly, many tropical fish keeping enthusiasts have lost an entire tank in only a day or two before ever diagnosing the disease.

Ich (Ichthyophthiriasis multifiliis)

Ich (Ichthyophthiriasis multifiliis) known to tropical fish keeping enthusiasts as White Spot Disease, is a parasitic ciliate that is arguably the most common ailment of all brackish, freshwater, and marine aquarium species.

Ichthyophthiriasis multifiliis is a protozoa that is wide spread in all freshwater fish but appears to be more common in aquarium species that are kept in close contact.

Almost every tropical fish keeping enthusiast at one time or another has housed fish that developed Ich, which is responsible for more fish deaths than just about any other fish disease.

LIFE CYCLE:

The life cycle of the Ich parasite includes a trophozoite (feeding or encysted) stage, a mature trophont stage, and an infectious theront (tomite) stage.

During the encysted stage, the Ich protozoan is called a trophozoite. The trophozoite attaches itself to the fish and begins to feed on the skin and tissue. As the protozoan continues to move around in the cyst feeding and growing on the tissue, the fish’s body will try to further encapsulate and wall it, off causing tremendous irritation.

Ich (Ichthyophthiriasis multifiliis)

The trophozoite eventually matures and is then referred to as a “trophont.” Each mature trophozoite (trophont) that falls off the fish will burst through the cyst wall and fall to the bottom of the aquarium where they begin to divide into thousands of new Ich infecting units called theronts (tomites).

The theronts, or tomites, are motile and swim around the tank looking for a fish to attach themselves to.

It is important to note that Tomites will only survive for 48 hours, however, if they can’t find a fish to attach to they will attach themselves to plants, rocks, filter media, etc. If you move a plant, piece of driftwood, or decoration from a tank infected with Ich, you have just infected the new tank.

Unless killed, the tomites will eventually penetrate the skin and gills of a new host to repeat the life cycle.  Depending on water temperature, the entire life cycle can take anywhere from 4 days to several weeks.

The encapsulation by the body of the fish during the trophozoite stage is why the Ich parasite is so difficult to treat in an aquarium environment.   Most medications cannot penetrate the wall of the cyst during this stage to destroy the Ich parasite.

The life cycle of the Ich parasite during the tomite stage progresses faster at higher water temperatures.   At 78-80 F, replication is completed in about 8 hours.   When replication is completed and the newly formed tomites are released into the water column, the parasite is most susceptible to a successful treatment regimen.

At lower temperatures replication takes considerably longer, as does treatment.

PHYSICAL SYMPTOMS:

Ich (Ichthyophthiriasis multifiliis)

Fish infected with Ich will be covered with white spots on the body and/or the gills which causes severe irritation.  Infected fish will try to rub or scratch off the protozoa on the sides and bottom of the aquarium.

As the disease progresses, the fish will display severe agitation, loss of appetite, respiratory distress, and eventually death.

Some or all of the following behaviors are symptoms of Ich infected fish:

• Abnormal behavior such as isolation, inactivity, etc.
• Anorexia or loss of appetite
• Balance problems
• Discoloration
• Flashing, rubbing, or scratching against objects
• Increased breathing rate (hyperventilation)
• Resting on the bottom
• Swimming upside down near the surface

Microscopic identification of an Ich lesion scrape will show a cyst between .5 and 1.5 mm in diameter with a horseshoe shaped nucleus.

CAUSE:

The primary cause of Ichthyophthiriasis is stress, with the most severe stress occurring during the shipping and handling of new fish.

Most fish that come in contact with the protozoan have strong immune systems that fight off the disease, but when the immune system is diminished and not functioning properly, usually because of stress, the lowered immune response allows the disease to take hold in the fish.

Farm raised and wild specimens imported by wholesalers, who distribute them to retailers, who finally sell them to tropical fish keeping enthusiasts, endure a tremendous amount of stress.

The Ich parasite is so wide spread that it is already present in a good number of collector’s, breeder’s, and wholesaler’s breeding ponds, holding tanks, and large aquariums.

Water quality, rapid changes in water temperature, improper diet, improper acclimation, shipping and handling, bullying by tank inhabitants, and a variety of other factors in an enclosed environment are all causes of stress that lowers the immune response in fish.

This is why Ich is most prevalent in newly purchased specimens.

TREATMENT:

We seldom recommend treating an entire tank for a disease, but Ichthyophthiriasis is the exception.

Because you cannot kill Ich while it is on the fish, removing the infected fish from a community tank to a quarantine tank does not solve the problem.

All effective Ich treatments are designed to kill the tomite form of Ichthyophthiriasis while it is in the tank.  The mature Ich organism (white spots) that you see on the fish does not die from the treatment, but will drop off in a couple of days during it’s normal life cycle.

The life cycle of the tomite is temperature dependent and because Ich can only be killed in the tomite stage, raising the tank temperature to between 78 and 80 F for at least 48 hours will speed up the life cycle and the parasites release from the host.

At higher temperatures, it takes approximately four days for the Ich life cycle to be completed.  However, at lower water temperatures (around 60 F) that goldfish and Koi prefer, it could take up to several weeks for any treatment to be effective.

When one fish in an aquarium has Ich, assume that the entire tank is contaminated.

You can treat the tank several ways.

Heat:

Most tropical fish are able to withstand temperatures around 86 degrees or more for short periods of time, but make sure your species can cope with higher temperatures before using this treatment.

Gradually raise the temperature in the tank to 90 degrees F. and hold for a period of two weeks.   To avoid stressing the fish, do not raise the temperature more than 2 degrees F every twelve hours.   After two weeks, bring the temperature back down to normal conditions.

The Ich in the tank will die in about 2 days, but keeping the temperature for two weeks will ensure an Ich free tank.

Keeping the water temperature (without fish) at 96 degrees F. for 3 to 4 days will completely eradicate Ich from the tank.

Salt:

Sodium chloride (NaCl) is effective against fungus, bacteria, external parasites, and provides essential electrolytes to fish.  Because it is cheap, readily available, never expires, and is easily used in low to high concentrations; it has been used by tropical fish keeping enthusiasts for years as an all around medication, but it has it’s drawbacks.

It cannot be used with most live plants, inverts, and scaleless species, and it is often difficult to determine the correct dosage for each species.  Salt overdoses have wiped out many freshwater aquariums.

Despite it’s drawbacks, here are three useful treatments.

1 Tbsp Salt per 3 gallons of water

Adding 1 tablespoon (Tbsp) of salt per 3 gallons of water will slightly irritate the slime coat on most species that creates a beneficial mucus on the skin that blocks parasites and microorganisms from harming the fish’s body.   Except for anchor catfish, this treatment is safe for most species.    Keep infected fish at this concentration for a week or so and increase if there is no improvement.

1 Tbsp Salt per 2 gallons of water

A concentration of 1 Tbsp of salt per 2 gallons of water combats a wider range of illnesses like Ich.   Keep infected fish in this concentration for 10 days or more and increase the dose if possible, if there is no improvement.

1 Tbsp Salt per 1 gallon of water

A high concentration of 1 Tbsp of salt per gallon of water will knock out virtually every illness however, it can be detrimental to scaleless fish and several other sensitive species.

Rasboras, danios, tetras, silver dollars, livebearers, most cichlids (and their fry), and even Neocaridina cherry shrimp are relatively salt tolerant.

Because salt does not evaporate or get filtered out of the water, overdoses most often occur when performing water changes.   Only add salt in proportionate amounts when doing water changes to maintain the necessary treatment level.

For example, if you are treating 100 gallons of water for Ich with 1 tbsp salt for 2 gal. water, you will initially need 50 Tbsp of salt.   If you make a 20% water change (remove 20 gallons of water), you need to add back 20% of the salt (or 10 Tbsp) to the new water to maintain the same concentration.

Unlike most medications, salt does not break down over time.

Salt and Heat:

Motile tomonts and theronts cannot survive in water with more than a trace of salt.   By increasing water temperatures and raising the salinity of the aquarium, the Ich parasite can be eliminated without harming more delicate species like such as elephantnoses and loaches.

Raise the water temperature to 82 – 86 degrees F. and gradually increase the salinity in the aquarium to 2 tsp/gal.   Instead of adding the salt directly into the tank; make a brine solution at the recommended ratio and over a few hours add it to the tank.

For example: When treating a 10 gal. aquarium, dissolve 20 tsp. of salt into a jug of warm, dechlorinated water and gradually add to the tank over a few hours.

Keep the salt in the tank for two weeks and gradually lower the salinity and temperature back to normal.

OTC Medications:

Over the counter Ich medications can be used to treat freshwater aquariums with species like tetras, barbs, cichlids, gouramis, livebearers, and goldfish but loaches, catfish, morymyrids, pufferfish, eels, and inverts like shrimp and snails react badly to many of them.

Malachite Green and formalin are good medications when used separately or in combination, and are readily available.   Methylene blue and copper treatments are also commonly used.

When using formalin products, it’s important that the product is fresh.   Old or outdated formalin precipitates into paraformaldehyde which is poisonous to fish.

Malachite green given at the recommended dose can also be toxic to some species like neons, piranhas, inverts, and many scaleless fish. Treat these fish with half the recommended dose and remove inverts.

Baths of salt, potassium permanganate, and quinine hydrochloride are also used but show no advantage over the more readily available medications.

Garlic:

Fresh garlic cloves, garlic juice, and/or commercial garlic products have been successfully used to eradicate Ich in tanks where snails, plants, shrimp, and delicate fish species are housed.   OTC products like Kent Garlic extreme or Sea Chem Garlic Guard mixed with the fish’s food improve the fish’s appetite and eliminate Ich sometimes within a couple of days.

Home made concoctions of freshly shredded and squeezed garlic cloves mixed with a bit of RO or tank water left overnight in the refrigerator and soaked into wafers, pellets, or sticks are proven cures.

In addition, a clove of garlic sliced, halved, or cut into quarters placed into the tank seems to eliminate the parasite in just a few days.  The garlic leaches into the tank water and the fish also seem to relish it.   For saltwater fish and freshwater species like plecos, catfish, snails, etc., where other products cannot be effectively used, it should be looked into.

Many tropical fish keeping enthusiasts remove all the fish from the community tank and raise the temperature to about 86 degrees F. or more for a couple of weeks before placing the fish back into the tank.

The removed fish are treated under observation in a medicated isolation tank to clear up the infection before being returned to the original tank.

PREVENTION:

• Only buy fish healthy fish that are free of all signs of disease.
• Never buy fish from a tank that contains dead, dying, or diseased fish.
• Do Not buy plants that are kept in a tank with sick or diseased fish.
• Quarantine all purchased fish and plants for a minimum of two weeks before introducing them into a community tank.
• Avoid buying newly acquired fish from retailers. Wait a week or so before purchasing them.
• Buy fish from the source when possible to reduce the amount of stress from shipping and handling.
• Avoid temperature, pH, Nitrate, Nitrite, and ammonia fluctuations to reduce stress.
• Avoid overstocking your tanks.
• Immediately remove any fish that show signs of Ich into a quarantine tank.
• Maintain pristine water quality with regular water changes.

Following these guidelines and treating infected fish promptly will greatly reduce the incidence of Ich (Ichthyophthiriasis multifiliis) and many other deadly diseases.

Anchor Worms (Lernaea spp.)

Anchor Worms (Lernaea spp.) are not actually worms, but crustacean, copepod parasites of the Lernaea species that attach themselves to the skin of freshwater fish and then bury their head into the muscle tissue usually under the fins, scales, gills, and oral cavity.

Although Anchor Worms can infect any fish species, most tropical fish keeping enthusiasts find them in Koi, goldfish, and other cyprinids housed in larger aquariums and ponds.

Although Lernaea infestations are not necessarily fatal to fish, their burrowing often leads to inflammation, secondary bacterial infections, and fungal diseases that kill the fish.   Large numbers of Anchor Worms in copepodid stages can kill smaller fish by damaging their gills and interfering with respiration.

Anchor Worms occur in stagnant and slow moving bodies of water and are most prevalent during the warm summer months.  The optimal temperature range for Anchor Worms is between 79 and 83° F.   Below 68° F, juveniles are unable to complete their development and below 57° F, the females will not reproduce.

Adult females however, will spend the winter on a fish host and lay her eggs when water temperatures warm up in the spring.

LIFE CYCLE:

Anchor Worms (Lernaea spp.)

Anchor Worms are related to shrimp, lobsters, and crabs and have a multi stage 18 to 25 day life cycle that does not require them to pass through an intermediate host.

Only a fish or amphibian is necessary for them to develop from egg to mature adulthood.

During the various stages of their development, Anchor Worms can live on or off of the host fish.

After a male and female Anchor Worm mate, the male dies and the female bores into the fish’s tissue where it eventually embeds her head into the muscle of the fish.   Within 24 hours the female matures into an adult and will start releasing eggs into the surrounding water from a pair of posterior sacs.   The eggs hatch within 24 to 36 hours at 77° F. and the life cycle repeats itself.

Newly hatched Lernaea are not parasitic and develop through three different stages in about 4 days.   They then molt into the first copepodid stage, become parasitic, and attach themselves to a fish usually on the gills.

Over the next week the Lernaea go through five different copepodid stages but do not permanently embed themselves into the fish’s tissue until the last stage.

In the final stage, the females can embed themselves into the host fish or move on to another fish.   The males detach themselves and die.

Female Anchor Worms can produce batches of up to 250 juveniles every two weeks for up to 16 weeks which is why they can quickly infest an aquarium or pond.

PHYSICAL SYMPTOMS:

Fish infected with Anchor Worms will have red and inflamed looking skin.    Closer investigation usually reveals a bloody red spot with a white to greenish looking thread protruding from the center, which is the adult female worm.

Because juvenile Anchor Worms are microscopic, there are no outward signs of infestation on the fish but you will notice the fish “flashing” or rubbing itself on the bottom or sides of your pond or aquarium as they try to rid themselves of the parasite.

When seen by the naked eye, the most commonly observed life stage of Lernaea is the adult female which looks like a thin hair or thread that is under an inch in length.

CAUSE:

Anchor Worm “disease” is caused by introducing new fish or aquatic vegetation into an aquarium or pond without being properly quarantined.    Fish with juvenile anchor worms or reproductive capable females under their skin will rapidly spread the parasite throughout an aquarium or pond.

TREATMENT:

Adult female Anchor Worms can survive 30 days on a fish host and are much hardier than the younger life stages.   If you are going to treat only a few fish, tweezers or forceps can be used to gently remove the visible female Anchor Worms.

To insure that all of the other life stages of the parasite are controlled, additional treatments of the entire system should continue for up to several weeks.

Other treatments available for anchor worms in an aquarium or pond environment include salt dips, formalin dips, and several over the counter antiparasitics like organophosphates, Dipterex, or Anchors Away.

• Potassium permanganate is generally considered the best treatment and can be used either as a “dip” or a complete pond/tank treatment.

A Potassium Permanganate dip at 100mg/ 2.5 gallons of water will kill the other life stages of the Anchor Worm. Dip the infected fish in the solution for 25 to 30 minutes and remove it if it becomes overly stressed. Transfer the fish into a clean isolation tank and maintain clean fresh water.

If you decide to treat the entire tank add 2 mg of potassium permanganate per liter of aquarium water.

• A 10 to 15 minute dip of 1 part water to 4,000 parts formalin is also effective in killing Anchor Worms. Use with extreme caution.
• Salt is also an effective medication for Anchor Worms if your fish can tolerate it.   Use 1 to 2 tablespoons per 5 gallons of tank water and perform water changes every day for 1 week.

Maintain the 1 to 2 tablespoons of dissolved salt ratio in the aquarium for 30 days.

• Dimilin (diflubenzuron) marketed as Anchors Away, is an effective treatment for Anchor Worm, Fish Lice, Gill Maggots (Ergasilus), and Flukes. It is less toxic than organophosphates towards fish.

In powder form a 10g to 2,642 gallon solution (25% Diflubenzuron)is a fairly forgiving dose. Although about 76% of the treatment remains after one week, a second treatment 10 to 14 days after the first treatment is needed to remove all stages of Lernaea spp.

(A level teaspoon equals approximately 2g)

• Dipterex (Trichlorphon) is a water soluable insecticide often used at 98% potency to kill Anchor Worm infestations in ponds. A 1 milliliter to 790 – 1320 gallons of water dose is used three times at 7 day intervals to treat large ponds.

Dipterex breaks down after a few days. The Anchor Worm eggs that survive the initial treatment and emerging parasites are killed by the follow up treatments.

Using any of the above treatments may require follow up treatments for bacterial and fungal infections caused by damage to affected tissue from burrowing Anchor Worms.

PREVENTION:

Isolate and quarantine new fish before introducing them into an existing system. High risk species like Koi and goldfish should be visually screened for adult female Anchor Worms and then monitored for 18 to 25 days during quarantine.   If parasites are detected, treat immediately with one of the above mentioned methods and maintain high water quality.

Sterilize the aquarium completely to minimize any re-occurrences.

Enteric Redmouth Disease (ERM)*

Enteric Redmouth Disease or (ERM) is a bacterial infection found in both freshwater and marine fish. Redmouth disease was first observed in in the 1950s in Idaho rainbow trout hatcheries. It is caused by the pathogen Yersinia ruckeri which is primarily found in cold water fishes like rainbow trout and other salmonids.

Being a cold water disease, it is relatively rare in tropical fish keeping circles where water temperatures are elevated, but it is occasionally found in Koi and goldfish ponds and aquariums. Mortality rates are generally high when not promptly treated.

PHYSICAL SYMPTOMS:

Enteric redmouth disease is characterized by hemorrhaging of the fish’s mouth, fins, and eyes.  It is seen as a reddening of the mouth, gill tips, throat, fins, and eventually (if not treated) total erosion of the jaw and palate of the fish.  As the disease progresses, hemorrhaging will also occur in the internal organs which causes the abdomen of the fish to be filled with a yellowish fluid.  The fish will exhibit a pot bellied appearance, show abnormal behavior and become anorexic.

CAUSE:

As with most preventable tropical fish diseases, Enteric Redmouth Disease is caused by poor water quality and overcrowding.

Although Redmouth Disease is mainly transmitted by direct contact with the infected fish, asymptomatic fish will often carry the bacteria in their lower intestines until a stressful situation occurs.   The infected fish then sheds the bacteria into the surrounding water through it’s feces where it can survive for several months in the sediment and other biofilm on surfaces of the aquarium or pond.

TREATMENT:

Several antibiotics are available for the treatment of Redmouth Disease in fish.   API Furan-2, API Melafix, and Fish Aid Amoxicillin are among some of the fish medications that can be used to treat Redmouth Disease.

PREVENTION:

The best way to prevent Enteric Redmouth Disease in ponds and cold water aquariums is by maintaining pristine water quality in the system.   Maintaining a low stocking level in ponds and aquariums is absolutely essential in the prevention of Redmouth Disease as well as most other bacterial infections.  Poor water quality is usually the culprit with most tropical fish diseases.

*Photo credit Alaa Eldin Eissa

Swim Bladder Disease in Oranda

Swim Bladder Disease, also called Floating Disorder, is a complication of the swim bladder that interrupts the fish from maintaining buoyancy.

Although it can affect any species of tropical fish that has a swim bladder, it is especially prevalent among Bettas and Goldfish.

PHYSICAL SYMPTOMS:

Fish suffering from swim bladder disease will have a distended belly which may eventually causes it to float upside down and appear dead.

Initially the affected fish will struggle to swim horizontally, have difficulty balancing and will float with its tail higher than its head until it can no longer hold it’s position.   It will also have difficulty surfacing.   These symptoms may occur after eating.

Many tropical fish keeping enthusiasts unaware of the condition assume that their fish has died when found floating upside down, but with proper care and an accurate diagnosis of the cause, Floating Disorder is treatable.

CAUSE:

Swim Bladder Disease is most commonly caused by compression of the fish’s organs which interferes with the proper functioning of the air bladder.   Organ compression does not necessarily have to affect the bladder directly; but can affect the organs surrounding the bladder.

Swim Bladder Disease can also be caused by any of the following:

• An enlarged stomach caused by overfeeding
• An enlarged liver caused by fatty deposits in the body, usually from improper diet.
• Constipation, which compresses the intestines and exerts pressure on the bladder.
• An enlarged stomach caused by inhaling too much air from the surface (mainly in goldfish)
• Cysts that cause enlarged kidneys
• Physical injury from hard impacts. Mishandling, dropping, etc.
• Bacterial infections from improper maintenance
• Bacterial infections from parasite infestations

TREATMENT:

Treating Swim Bladder Disease obviously depends on the type of disorder and the underlying cause that created the problem.

If the fish suffered from a physical injury or had a birth defect, it is unlikely that the Floating Disorder can be successfully treated.

The first and foremost treatment is to water quality.

The water quality in the affected fish’s aquarium should be pristine.   Making 20 to 30% partial water changes every two to three days virtually assures pristine water quality.

Aquarium salt should be added at a level of 2 tsp per gallon.   Adding salt will maintain hydration and aid in electrolyte balance.   Be careful that the species being treated is not sensitive to salt like most catfish, loaches, eels, etc.

Nutrition is one of the main culprits of Swim Bladder Disease.

Overfeeding can cause compression of the swim bladder.   Treat this problem by not feeding the affected fish for three or four days. Withholding food for 3 or 4 days allows excessive gasses to be flushed from the fish’s system.   Short term feeding of crushed peas also helps the removal of excess gasses from the fish’s gastrointestinal system.

After treatment, feed the affected fish very sparingly two or three times a day.   If there is uneaten food in the tank after 5 minutes, you are overfeeding.

What you feed your fish can also cause Swim Bladder Disease.

Some fish species should not be fed high protein foods like live or frozen tubifex, bloodworms, beef hearts, etc.   Discus for example are fine with this high protein diet, but many other species will suffer kidney damage which can lead to Floating Disorder.   Many cichlid species require a herbivorous diet and when fed the wrong protein source could develop a gastrointestinal condition known as bloat.   Feed your fish the  balanced diet they require to treat Swim Bladder Disease.

Improper Water Temperature

Low water temperatures can cause indigestion in many tropical fish species.   Indigestion or undigested food results in bloated bellies that causes buoyancy problems.   When indigestion is suspected, increase the water temperature to 80 to 82 degrees F. and cut back on the amount of food for a few days.   Adding a small amount of aquarium salt to the tank water also aids the process.

If symptoms persist, feed the affected fish a small amount of fresh spinach or a green pea without the skin as a laxative.

If you maintain pristine water conditions in your aquarium and the Nitrates, Nitrites, and Ammonia levels are correct, it is unlikely that Swim Bladder Disease is the result of environmental conditions.

Bacterial infections are normally the result of poor water quality due to over crowding, overfeeding, parasites, unclean conditions, etc.

When parasites are suspected as the cause and more than one fish is affected by Swim Bladder Disease, an antibiotic/anti parasitic treatment regimen may be necessary.   Isolate the affected fish in a hospital tank, lower the tank water to about 4 inches, and carefully follow the instructions provided.    Avoid using antibiotics whenever possible.

Generally, when more than one of your tropical fish suffers from Swim Bladder Disease on a regular basis, it is most likely that diet, overfeeding, or poor water quality is the culprit; all of which can be easily corrected.

If only one fish suffers from Swim Bladder Disease, and the above treatments do not reverse the problem, it may not be caused by environmental factors that are treatable and the fish may have to be euthanized.

PREVENTION:

Swim Bladder Disease is best prevented by providing your tropical fish with a pristine environment, the correct water temperature, and regular feedings of a varied, high quality diet.

Keeping the tank water immaculately clean and between 78 to 80 degrees F will eliminate most problems before they occur.

Adding a small amount of aquarium salt to the tank (depending on species) adds electrolytes and improves the well being of the fish.

Viral Hemorrhagic Septicemia – VHS

Septicemia or Sepsis is a bacterial infection in the bloodstream of the fish that is characterized by sluggishness, lack of appetite, fin damage, reddish discoloration, bulging eyes, and/or clamped fins.

PHYSICAL SYMPTOMS:

Septicemia

Septicemia can be detected initially by redness under the scales of the fish, lesions of hemorrhage, and ulcerations anywhere on the body.  Although it can be concentrated in only one area of the body, it will often spread all over the fish’s body.

Although Septicemia is more visible around the face of the fish, it is almost impossible to detect in dark or red colored species.

Open wounds on healthy fish are pinkish in color and normally heal quickly.  A gray, black, or fuzzy wound that is discolored around the site of the wound may be infected by Septicemia and should be treated quickly.

Septicemia occasionally shows up as a secondary infection to Popeye (exophthalmia) and can also lead to Dropsy.

Other symptoms like color loss, loss of appetite, general sluggishness, or clamped fins can also be an early indication of Septicemia.  

Watch you fish for abnormal behaviors to recognize diseases when they occur.

CAUSE:

Septicemia can be caused by either a bacterial infection (bacterial hemorrhagic septicemia – BHS) or a viral infection (viral hemorrhagic septicemia – VHS).

Nine species of bacteria have been identified as the cause of Hemorrhagic Septicemia including:  Aeromonas hydrophilla, Aeromonas sobria, Edwardsiella tarda, Flavobacterium columnare, Plesiomonas shigelloides, Shewanella putrefaciens, Streptococcus agalactiae, Vibrio cholera, and Vibrio fluviaris.

Septicemia occurs when infestations of external parasites cause wounds on the skin of the fish, when open wounds become infected by bacteria and viruses,  and when bacteria is consumed by the fish in it’s food.

Common Septicemia will usually occur when an open wound is not kept clean.  When humans injure themselves they need to keep the injury clean in order to prevent infection.  Fish also need to keep their injuries clean when they become wounded by mishandling, predation, external parasites, fights with other fish, etc.   The best way to do this is by performing regular water changes to keep toxins at bay.

Septicemia can also be contracted when fish are fed live and/or frozen foods infected with food born pathogens; usually associated with poor quality tubifex and blackworms.

TREATMENT: 

We usually recommend treating bacterial diseases with antibiotics* sparingly, however, with Septicemia their initial use is strongly recommended.

Septicemia in the blood can quickly overcome an infected fish and an antibiotic treatment regimen is the quickest and most effective way to treat this disease.

Although most aquarium antibiotics are made to dissolve in the tank water where they can be absorbed by the fish, Septicemia is an internal bacterial infection that requires a medicated antibacterial fish food to better target the infection.

Amoxicillin, gentamicin, ofloxacin and sulfamethoxazole/trimethoprim are the drugs of choice for the treatment of Bacterial Hemorrhagic Septicemia.

Aquatronics Osymanna flakes have been around since 1980 and are extremely effective for treating freshwater and marine fish.

Soaking pellets in a concentrated mixture of Mardel’s Maracyn and Maracyn 2 is also an effective method of treating Septicemia.  Just chop up the amount you would normally use to treat the tank, add a few drops of water, soak several pellets in the mixture for 10 minutes or so, and feed the affected fish.  Add the pre-measured mixture to the tank as per directions.

Because there is no way to accurately measure exactly how much medicated food the fish is eating, especially with the loss of appetite that is commonly associated with the disease, the method is not fool proof.  This is why it is so important to administer the medicated food while the fish is still eating.

If the fish is no longer eating, employ the standard method of adding antibiotics to the tank water.

Because most tropical fish keeping enthusiasts have no way of determining the specific type of bacteria that infected the fish, a broad spectrum antibiotic or combination (like those below) that treats both gram positive and gram negative bacteria is highly recommended.

• Mardel’s Maracyn and Maracyn 2 in combination
• Aquarium Pharmaceuticals Triple Sulfa
• Kanamycin Sulfate (for fish that won’t eat)

PREVENTION:

• Perform regular water changes and testing to prevent bacteria buildup that can lead to Septicemia.
• Do Not overcrowd your tank.  Fish wastes builds up quickly even with the best of filtration systems.
• Do Not overfeed your fish.  Small quantities of quality foods fed two or three times daily is preferable to a single feeding and minimizes waste buildup.
• Only keep compatible species in a community tank environment.  Watch new additions for bullying or nipping and separate or remove them when necessary.   Watch for changes to eyes,  fins, tails, body, appetite, and behavior.
• Quarantine new fish before placing them in a community tank.  It is easier to spot and treat fish diseases in a quarantine tank than in a community environment.

*  Antibiotic resistance is a major problem facing tropical fish keeping enthusiasts throughout the world.   

Currently there are several strains and one particularly virulent strain of Flavobacterium columnare that has made its way into the aquarium hobby that has been known to kill fish in less than a day and may be untreatable.

Antibiotics should only be used when necessary or when all other treatment regimens fail.   Following the manufacturer’s instructions will help to avoid antimicrobial resistance and residues in fish, and can minimize the evolvement of newer, stronger strains of bacteria that cannot be handled with antibiotics.   

Dropsy in Goldfish

Dropsy also known as Malawi Bloat, is a condition that occurs both in holding ponds and tropical fish keeping aquariums that when not treated promptly, is almost always fatal to the fish.   Dropsy is a bacterial fish disease that targets the internal organs causing the accumulation of water in the belly of the fish which is exhibited by swelling of the abdomen and protruding scales.

PHYSICAL SYMPTOMS:

The most obvious external symptom of Dropsy is the characteristically swollen belly of the fish which means that the internal organs have already been injured.   At this stage, it is unlikely even with prompt medical treatment that the fish will survive.   Other easily detectable symptoms include swollen eyes, pale gills, swollen bloody colored anus, pale feces, clamped fins, a curved spine, and protruding (pine cone like) scales that stand out from the fish.  Although some specimens with Dropsy may not show any visible symptoms, a loss of appetite and lethargic movement with the fish hovering around the top of the tank instead of swimming normally could indicate the early stages of the disease.

All of the above symptoms progress aggressively, which is why early detection is so important to the prevention and spread of Dropsy to other inhabitants of the tank.

If you notice even one of the these symptoms, start treatment immediately.

CAUSE:

Dropsy is caused by a common gram negative bacteria called Aeromonas which is present in all aquarium environments and attacks the immune system of the fish.   Although it displays a combination of symptoms that is actually more of a health issue then a disease, Aeromonas can lead to Dropsy only when the immune system of the fish is failing or has already failed.

Decreased immune system stability occurs when fish are under stress, which can be the result of several factors.

• Poor water quality
• Changes in Nitrate and Ammonia levels
• Drastic changes in water temperature
• Bullying and aggressive behavior
• Poor or unbalanced diet

When fish in an enclosed system are stressed from anything at all, the immune system will start to fail and the Aeromonas bacteria begin to do their work.   The bellies of the infected fish will start to drop down and appear bloated as the bacteria infects the immune system.  When the swelling of the belly is sudden, the probable cause is probably Aeromonas however, when the swelling is gradual, parasites or cancer could be the culprit.

There is virtually no danger of your fish contracting Dropsy if they are healthy and thriving in a healthy environment without any of the above stress factors.

TREATMENT:

Treatment for Dropsy depends on how quickly the disease is diagnosed. Most tropical fish keeping enthusiasts euthanize infected fish to prevent healthy fish from being infected, but if you can detect the disease in its early stages, infected fish can be treated successfully.

This is what can be done:

• Move all infected fish into a bare hospital tank with an air powered sponge corner filter.
• Change 50% of the tank water in the infected aquarium
• Monitor healthy fish for symptoms to prevent the further spread of the infection.
• Add 1 tsp of salt per gallon of tank water to the hospital tank and maintain spotlessly clean conditions by performing weekly 50% water changes.
• Provide the highest quality food you can acquire to boost the fish’s immune system. When the fish exhibit signs of improvement, maintain the diet until all symptoms are gone.

Most of the time, a healthy diet and immaculate water quality will “perk up” the immune systems of the fish.

• If the fish still do not show signs of improvement, start treating the infected fish with a good antibiotic like Maracyn 2 or an equivalent. Usually a 10 to 12 day treatment will destroy any signs of Dropsy.

If the fish does not respond favorably after 3 weeks or so, the specimen may need to be humanely euthanized.

KanaPlex, ParaGuard, Furan-2, Melafix, SulfaPlex and several other over the counter bacterial medications also work on Dropsy.

PREVENTION:

All fish are prone to stress and when stressed over a period of time, their immune systems will eventually fail allowing them to become prey to a variety of diseases.

Like all bacterial infections, the best way to prevent Dropsy is to provide your fish with a clean, healthy, aquarium environment.

We know that a weakened immune system can cause Dropsy in freshwater and marine tropical fish.   This can be because of poor water quality, wide fluctuations in water parameters, constant stress, bullying from tank mates, malnutrition, etc.

Because poor water quality is the number one stress factor for all tropical fish, maintaining a clean aquarium should be the number one priority for all successful tropical fish keeping enthusiasts.

You can prevent Dropsy and virtually all other tropical fish diseases by adhering to the following:

• Change the tank water on a regular schedule.
• Clean and replace filter medium on a regular basis.
• Clean power heads and pre-filters on a regular schedule.
• Regular checks of Ammonia and Nitrite levels.
• Avoid drastic changes in water temperature.
• DO NOT over populate your aquarium.
• Quarantine new additions to your aquarium.
• Remove constantly bullied or bullying fish into another aquarium when observed.
• Be careful about the quality, how much, and how often you feed your fish. Never overfeed.
• Note the shelf life of prepared fish foods and use within a couple of months of opening or before the expiration date.
• Provide your fish with a mixed diet of prepared, live, frozen, or freeze dried foods.

Rainbow Wolf Fish (Erythrinus erythrinus)

Rainbow Wolf Fish (Erythrinus erythrinus) known to tropical fish keeping enthusiasts as High Fin Wolf Fish or Red Wolf Fish are found in Brazil, French Guiana, Peru, Trinidad and Tobago,  and Venezuela.

Rainbow Wolf Fish (Erythrinus erythrinus)  are usually found among surface vegetation in the very shallow waters of small river tributaries, swamps, the margins of forest lakes, marshes, pools, and ditches of their range.

The Rainbow Wolf Fish has a modified swim bladder that allows it to breath air and survive in stagnant or oxygen depleted waters and like “walking catfish” they have been know to travel short distances over land when their native waters begin to dry up.

Rainbow Wolf Fish are carnivorous predators that sport a mouth filled with sharp teeth.   They show absolutely no fear and will viciously strike at any object introduced into their tank.

Rainbow Wolf Fish (Erythrinus erythrinus)

Rainbow Wolf Fish vary in color depending on locality.  In general they have a light to dark brown body color with a wide lateral line that runs from the eye to the caudal fin.  Their set back dorsal and caudal fins are brown tinged with yellow to reddish orange and their pelvic and ventral fins are translucent white to yellow.  Although most Rainbow Wolf Fish have bone to white undersides, a Peruvian variant has a brightly colored orange belly.   Adult females can be identified by their more slightly rounded bellies.

A species of juvenile Rainbow Wolf Fish in Grench Guiana has a color pattern that mimics a species of female Rivulus Killifish.    Male Rivulus are attracted to the mimic “female” and are promptly gobbled up by the Wolf Fish.  The strategy ceases as the Erythrinus grows into adulthood.

Genetic studies of different populations have determined that Erythrinus erythrinus is a species complex and not just a single species.  One other recognized species (Erythinus kessleri) that grows to a maximum length of 7.5″ is found in the Itapicuru River in Brazil and is virtually unheard of by tropical fish keeping enthusiasts.

Erythrinus erythrinus can be housed with similarly sized South American species in a large tank but because of their ferocity as adults, they are better suited to a densely planted, dimly lit, single species aquarium of at least 55 gallon capacity with a sandy or fine gravel substrate, plenty of floating plants, and plenty of hiding places in the form or driftwood or bogwood roots.

Erythrinus erythrinus  are extremely intolerant of conspecifics and like male Bettas, will often fight to the death.  Smaller fish introduced into the tank will be quickly eaten, so be careful when selecting tank mates if you plan on keeping them in a community environment.

Rainbow Wolf Fish are excellent jumpers and require a tightly fitting tank to prevent them from escaping.  Although they can handle a wide variety of water parameters, they need a good filtration system with little to no water movement to keep them happy.

There are no reports of Rainbow Wolf Fish being successfully bred in an aquarium environment.  This is probably due to their behavior towards conspecifics.

In their natural environment, Rainbow Wolf Fish feed on insects, worms, and other fish.  In an aquarium environment, they require live or frozen earthworms, mussels, prawn, shrimp, and white fish.  They will usually refuse freeze dried or prepared carnivore pellets or flakes but they have been known to accept them when gradually offered over time.  Because of the possibility of transmitting parasites or other diseases into the tank, refrain from feeding them live “feeder fish”.

Rainbow Wolf Fish are not often available to tropical fish keeping enthusiasts but on occasion, specialty fish shops, importers, and online fish auction sites do have them available as juveniles at  2 to 4 inches in length and occasionally as adults.

Rainbow Wolf Fish (Erythrinus erythrinus)

Minimum Tank Size: 55 gallons
Care Level: Difficult
Temperament: Highly Aggressive
Aquarium Hardiness: Hardy
Water Conditions: 72-79°F, 2-25°H, pH 5.5-7.5
Max. Size:
Color Form: Red, Brown
Diet: Carnivore
Compatibility: Single species
Origin: Peru, Brazil, Venezuela
Family: Erythrinidae
Lifespan: 4-10 years
Aquarist Experience Level: Advanced