Most freshwater and saltwater fish losses by wholesalers, retailers, and tropical fish keeping enthusiasts can correctly be attributed to improperly  unpackaging them upon arrival at their destinations.

After purchasing fish online or from your local tropical fish keeping facility, it is imperative that you acclimate them as soon as possible.

The following explains the water chemistry encountered with fish transport:

As fish breathe, they produce carbon dioxide in their shipping containers.   When shipped long distances, the carbon dioxide is dissolved in the shipping water creating an acidic condition that lowers the pH in the shipping container.

Fish wastes created during transport break down into ammonia that is present in the water as either NH3, NH4+, or a combination of both.   Although NH3 and NH4+ are both toxic to fish, NH3 is the most detrimental.     During extended shipments as the pH is lowered, the amount of NH3 is reduced and the amount of less damaging NH4+ increases; basically making the ammonia non toxic to the fish.

Essentially, the carbon dioxide in the shipping container acts as a tranquilizer to the fish, which is why specimens can be shipped from India, Bali, New Guinea, and other far away locations in closed containers.

Once the shipping bag is opened and the water is exposed to the outside air, the carbon dioxide in the bag escapes and the pH of the water immediately begins to rise, making the ammonia deadly to the fish.

This is why you should NEVER ADD WATER FROM THE SHIPPING CONTAINER TO YOUR AQUARIUM or FROM THE AQUARIUM TO THE SHIPPING CONTAINER.

Because many species tolerate changes in water quality differently; several acclimation methods have been developed by trans shippers, wholesalers, retailers, and hobbyists to control the rate of chemical change during the unpacking process.

Below are three of the most commonly used acclimation methods:

Drip Method:

This method is recommended for very sensitive aquatic life including fish, corals, sea stars, sponges, sea horses, shrimp, clams, snails and other invertebrates.

You will need a clean 5 gallon bucket that is only used for aquarium maintenance, a length of tubing and a plastic air valve. When acclimating fish and invertebrates, use a separate container for each.

Keep the lights in the room you will be unpacking your specimens in dimmed to reduce stress as much as possible.

Float each sealed shipping bag in the aquarium you will be placing your specimen for about 15 to 20 minutes, to adjust the temperature in the bag to the water in the tank.

Empty the contents of each shipping bag with the shipping water into the buckets which should be tilted enough to keep the specimen submerged.   Try not to expose sensitive invertebrates to the air.

When all the specimens are unpacked into the tilted bucket, there should be enough water in the bucket to keep it in an upright position.

Run a length of tubing from the aquarium into each bucket you are using and start a siphon.   When the water starts flowing, install the plastic air valve at the bucket to adjust the drip rate to 2 or 4 drips per second.   This rate should double the volume of water in the bucket every 30 minutes or so.

When the water volume in the bucket doubles; discard about half of the water and continue the drip until the volume doubles once again.    This should take about another 30 minutes.

After an hour or so, the specimens should individually be able to be transferred into the aquarium or quarantine tank by gently removing them with a net.

When acclimating corals, sponges, and decorative clams that should never be exposed to air; gently scoop them out of the bucket with a specimen bag ensuring that they are fully covered with water.

Submerge the bag underwater in the quarantine tank and gently remove the specimen from the bag.    Then seal off the bag by twisting the opening shut while it is still under water, and discard both the bag and water.   A small amount of diluted water from the bucket in the bag will escape into the aquarium, but the amount is negligible.

Keep the lights in the aquarium or quarantine tank off for at least 8 hours to help the specimens adjust to their new surroundings.

Floating Method:

This method is recommended for acclimating most freshwater and hardy marine species.

Float the sealed shipping bag in your aquarium or quarantine tank for 15 minutes to slowly adjust the water temperature in the bag to the water in the aquarium.

After 15 minutes, cut the bag open and roll the top edges over to create a lip with an air pocket to allow the bag to float.    Add a half cup of aquarium water into the bag every 15 minutes until the bag is full.

Discard half the water in the bag and again float the bag in the aquarium. This time add a half cup of aquarium water into the bag every 4 minutes until the bag is full. Then gently net out the fish into the aquarium and discard the water and shipping bag.

Keep the lights in the aquarium or quarantine tank off for at least 4 hours to help the specimens adjust to their new surroundings.

Quick Float Method:

After your fish is brought home, immediately place the shipping container into your tank, preferably an isolation tank, and allow it to float for at least 20 minutes to bring the water temperature in the container to the temperature of the tank water.

Open the shipping container and slowly pour the contents of the shipping container through a net into a waste bucket and release the fish into the isolation tank.

When a large number of fish are being received in a large box shipping container, drain most of the container water off and net out a couple of specimens at a time.   Do not net all the fish at once or you can damage the fish as they are forced together in the net.

With large specimens, Plecostomus, or catfish, wet your hands and place them into the isolation tank by hand.

Sometimes after extended periods in the shipping container, fish may appear to be dead or are barely breathing.   This common “possum like” behavior is due to stress from shipping and handling.

Turn off all lighting in the isolation tank for at least 8 hours and let the fish alone until they revive.   Do not feed the fish during this stage.

BE PATIENT. It can sometimes take several days for fish to fully revive from the stress of a long shipment and even longer for them to regain their colors.

Change 30 to 40% of the water in the isolation tank daily for the first week, and every other day for the second week.  If the fish show no sign of disease or stress after the second week in isolation, you can confidently move them to their permanent tank.

Sometimes even when you do everything right, your fish will not survive transport.

Before you give up and call in a D.O.A., watch the fish’s gills for several minutes to make sure it is still not breathing.    Several species of saltwater fish frequently lay on their sides for several hours to a couple of days before fully “coming to”.