Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish (Rhinecanthus aculeatus) known to tropical fish keeping enthusiasts as Humuhumu Triggerfish (the official state fish of Hawaii), Blackbar Triggerfish, Lagoon Triggerfish, or Picassofish is found throughout the Indo-Pacific and ranges from East Africa eastward through northern Australia to the Hawaiian, Marquesas, and Tuamotu islands, north to southern Japan.

Picasso Triggerfish are a shy, highly territorial species that are most commonly found in the subtidal reef flats and shallow protected lagoons of their range at depths from 3 to over 160 feet where they can be seen grazing on detritus, mollusks, crustaceans, sea urchins, worms, algae, corals, tunicates, forams, small fishes, eggs, and just about anything they come across.

Adults prefer open flat, sandy areas of the reef with scattered patches of rubble, while the more secretive juveniles are found hiding in rocky rubble.

Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish have a large oval shaped body with small, prominent eyes, and strong jaws that are used for opening up shells and corals.

Picasso Triggerfish colors are a true work of art of light tans, whites and painted splashes of yellow, blue, black, and brown.

They have a grayish tan body color with dark gradients towards the rear and a bright white belly.   The top of the head above the eye is covered with bright blue and black stripes, the small prominent orange or yellow eyes sit at the top of the head, and a bright yellow or black stripe runs from the mouth towards the lower portion of the body, just above the white belly and ends below the eye.

Picasso Triggerfish require a spacious FOWLR tank of at least 180 gallon capacity with a sandy or coraline substrate, and plenty of live rock arranged into caves, overhangs, crevices, for them to hide among.

Rhinecanthus aculeatus are NOT reef safe.   They can be very aggressive towards fish and invertebrates and although they may not initially bother any corals in the tank, they will greedily eat larger crabs, sea urchins, and shrimp.   Some tropical fish keeping enthusiasts have had luck keeping Humuhumu Triggerfish in full reef setups when introduced as juveniles, but their aggression grows with age.

Picasso Triggerfish are best housed alone or with other aggressive species in a fish only tank.

Like all triggerfish, this species requires stable water conditions, a varied diet, and constant monitoring of their behavior.

An excellent protein skimmer and wet dry filtration system is required along with a wave system to maintain water quality and movement.

Picasso Triggerfish display distinct pairing and have been bred in an aquarium environment but success is challenging and rare.

Mating is a mixture of polygyny, monogamy, and promiscuity; with polygyny being the primary mating process.

Both sexes guard and maintain their territories for up to eight years or longer.   A male’s territory may overlap with one to five female territories and their mating system is described as haremic.

Pairs spawn around sunrise.   After external fertilization takes place, the egg masses are attached to the sand, coral rubble, or algae and hatch on the same day around sunset.

The females guard and care for eggs until they hatch.   She stations herself above the eggs and fans them with her pectoral fins for about 12 to 14 hours to improve aeration while aggressively chasing away any intruders, including divers.

Fortunately their relatively small size makes them much less dangerous than the larger Titan Triggerfish or Moustache Triggerfish (Balistoides viridescens) of the same family.

Picasso Triggerfish reproduce multiple times over their lifetimes.

Humuhumu Triggerfish are carnivores that in their natural habitat mainly prey on invertebrates such as snails, crabs, clams, mussels, shrimp, urchins, and about any hard or soft shell animal.   In an aquarium environment they should be fed a varied diet of meaty foods including squid, krill, clams, small fish, mussels, and hard shelled shrimp to help wear down their ever growing teeth.   Feeding Picasso Triggerfish two to three times a day is recommended

Picasso Triggerfish (Rhinecanthus aculeatus) are available to tropical fish keeping enthusiasts from a variety of online suppliers and specialty fish shops at reasonable prices that vary according to size and area of collection.

Approximate purchase sizes: Small: 1″ to 2″; Medium: 2″ to 3″; Medium/Large 3″ to 3 3/4″; Large: 3 3/4″ to 4 1/2″; X Large 4 1/2″ to 5 1/2″. Prices for small Keynan specimens start at around $ 69.99.

Picasso Triggerfish (Rhinecanthus aculeatus)

Picasso Triggerfish (Rhinecanthus aculeatus)







Minimum Tank Size: 180 gallons
Aquarium Type: FOLR
Care Level: Easy
Temperament: Aggressive
Aquarium Hardiness: Hardy
Water Conditions: 72-78° F, dKH 8 – 12°, pH 8.1 – 8.4, sg 1.020-1.025
Max size: 10″
Color Form: Black, Blue, Orange, Tan, Yellow
Diet: Carnivore
Compatibility: Reef NO
Origin: Indo-West Pacific and Hawaii
Family: Balistidae
Lifespan: 10 years
Aquarist Experience Level: Intermediate

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