Saltwater Aquarium Blog

Picasso Triggerfish – Saltwater Aquarium Blog

Would you agree with me that the Picasso triggerfish, or Humu Humu, is truly a work of art. The fish has markings that resemble an abstract painting. As an easy to care for triggerfish, the Picasso is a very popular saltwater fish species. Want to know how to care for one in your saltwater aquarium? Let’s dive right in.

Quick Facts About the Picasso Triggerfish:

  •  Scientific Name: Rhinecanthus aculeatus
  • Common Names: Humu-Humu, Lagoon Triggerfish, Piccasofish
  • Max Size: 10 Inches
  • Minimum tank Size: 100-Gallons
  • Aggression Level: Aggressive
  • Color: Blue, White, Brown, Yellow, Black
  • Care Level: Beginner
  • Most Active: Day
  • Lifespan: 10 Years

Natural habitat

The Picasso Triggerfish can be found in the Indo-pacific ocean and the red sea. Most commonly it can be seen around Hawaii, Polynesia, and the Philippines. This fish tends to be found in the sandy parts of reefs swimming around actively and generally found in more shallow parts of reefs, where there are rocks for it to hide away in. It’s the official fish of the state of Hawaii, where it is called:

humu humu nuku nuku apua’a

Or humu humu, for short. This fish is extremely territorial and guards it’s home from all matters os sea life. They have even been known to try and chase off divers.

Picasso triggerfish

Picasso triggerfish aquarium conditions & behavior

The Picasso triggerfish does well in the usual saltwater aquarium water conditions:

  • About 78 degrees F
  • 1.025 specific gravity
  • pH ~8.2

They tend to be best kept in a fish-only environment, with other aggressive fish. Since they can grow to be 10-inches long, it’s probably best to keep them in a tank that is about 100 gallons, or larger.

The Picasso Triggerfish is incredibly territorial and will cause trouble with tank mates if it feels it’s home is too cramped. In the wild this fish is solitary outside the harem of females it will occasionally meet with during the breeding season.

I have seen them kept in large, relatively open fish-only tanks, but if you want to recreate their natural environment, you may want to keep them in a tank filled with live rock, where it will periodically hide in the crevices.

Picassos are famous (or is it infamous) for rearranging and redecorating your tank…because…well…they are built like a tank (the other kind). They might dig, they might chew and the might just knock stuff over.


humu humu picasso triggerfish

Watch out! Triggerfish bite

Be careful when putting your hand in the tank–especially when first introducing the fish to your tank. Picasso triggerfish have been known to bite, and their teeth pack a punch…or bite…yeowch!

As mentioned earlier, humu humus are also extremely territorial, which might give them another reason to bite.

With that said, they can and will become acclimated to your tank. They are smart, will recognize you as the source of food and can be trained to take food out of your hands.

What did you say?

What’s that noise you say? Does it sound like grunting? If so, that maybe your Picasso triggerfish trying to get your attention. That’s right, this species communicates (oftentimes aggression) by grunting.


Picasso triggerfish compatibility

The Picasso triggerfish is NOT REEF SAFE.

Sorry, I didn’t mean to shout. They love to eat invertebrates. Even if they aren’t eating your inverts, they might knock down or otherwise terrorize your corals. They will attack less aggressive fish. So they are best kept in a fish-only tank with other aggressive fishes, like the snowflake eels, Lionfish, and similarly sized surgeonfish.

Although solitary, some fish keepers have had success with keeping multiple Picasso fish in a tank when introduced as juveniles. Remember to check the tank daily to make sure there isn’t bullying going on between your community. Another important tip would be to avoid adding fish (even aggressive ones0 that are significantly smaller than your humu humu.

Small triggerfish



Reproduction & Sexing

In the wild, the territory of the male triggerfish will usually overlap with a few breeding females. The male will create a harem around himself to breed with during the mating season. The fish generally spawn at dawn, where the male will fertilize the eggs and then leave them in the care of the female. Then the male moves on. This process requires an extremely large amount of territory that isn’t possible to recreate in-tank environments.

After the eggs are laid, the female will watch over them while fanning them with her fins. Picasso fish eggs hatch incredibly fast, and most larvae will hatch and swim away by sundown of the same day.


The humu humu triggerfish is not a picky eater. This fish is, for the most part, carnivore. Their natural foods are: clams, snails, shrimp, krill, squid, etc.,and will need to be fed meaty foods to survive.

Because their teeth will keep growing, you need to give them some foods, with shells, that will wear down their teeth. This can be in the form of frozen meals or live foods. Try to vary the type of seafood you feed the R. aculeatus to provide them with a varied diet.

Rhinecanthus aculeatus also known as the picasso triggerfish or humu humu

Where to buy a humu humu

Considering how amazingly beautiful they are, the humu humu is a rather inexpensive fish to purchase, especially as juveniles. This is presumably because they are bold, slow swimmers are are likely relatively easy to catch (by saltwater fish standards).

They should be available at high quality local fish stores or at the major online retailers. This fish is known to handle the stresses of shipping well

Whether to Buy a Picasso Triggerfish or Not

The Picasso triggerfish is a bold, beautiful, aggressive fish that is fun to watch and easy to keep alive, but extremely territorial. They grow quite large (10 inches) and require a large tank. They are incompatible with nearly any reef invertebrates, eating the mobile inverts and knocking over the others.

With that said, if you want to have a very cool fish only aquarium, this brightly colored fish will learn to recognize you when you feed it, the state fish of Hawaii could be a great choice.

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