Picasso triggerfish [109K]

This Picasso triggerfish is also known as the Lagoon or Blackbar triggerfish, or more generically, hu-mu hu-mu (referring to all triggerfishes).  It is a colorful relative of puffers, porcupinefishes, boxfishes, and filefishes-- all members of the order Tetraodontiformes. Triggerfish have a sharp spine, or trigger, shown here folded down into its groove as the black streak on the top of the fish. I know from experience trying to photograph triggers that if they are chased long enough, they eventually take refuge in a reef hiding place, such as in a small hole in the reef near the bottom of a coral outcropping. The trigger turns on its side to enter. After entering the hole, if the fish raises its trigger, it is nearly impossible to remove. I suspect the hiding place the fish usually prefers is its burrow, since triggerfish are territorial and known to sometimes sleep on their side.

Triggerfish are tough and sleek, favoring shallow waters of the reef. Their tough skin and fused teeth make them capable of successfully attacking spiny sea urchins to get to the soft flesh. They also eat crabs, mollusks, worms, other fish, algae and are even known to nip at the tips of hard corals.  This species only grows to about nine to ten inches (about 25 cm) but some others, such as the Titan triggerfish, may grow to 30 inches (75 cm). They are found in many areas of the Pacific from Hawaii to the Maldives, and even the southeast and east central Atlantic and the Red Sea.

Early Hawaiians used this and another trigger species, R. rectangulatus, in religious ceremonies, naming them for their pig-like habits of rooting through the substrate for food, and grunting when disturbed.

Identification: Rhinecanthus aculeatus

related links:

more about the Picasso triggerfish from Fishbase

more on R. aculeatus from the Univ. of Michigan's Animal Diversity Web*
*note: though otherwise useful, I believe the above article improperly describes R. aculeatus as the "Reef triggerfish", not R. rectangulus as described by other sources.

nomenclature of triggerfishes explained by About Saltwater Aquariums

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