The 40 species of triggerfish are scattered throughout the world’s seas and are familiar to divers and aquarium aficionados. Largest of all is the stone triggerfish, which reaches up to 3.3 feet (1 meter) long, found in the Eastern Pacific from Mexico to Chile.
These bottom dwellers dig out prey, such as crabs and worms, by flapping away debris with their fins and sandblasting with water squirted from their mouths. They also use very tough teeth and jaws to take on sea urchins, flipping them over to get at their bellies, which are armed with fewer spines. Triggerfish wreak such havoc on less fortunate reef dwellers that smaller fish often follow them to feast on their leftovers.
The Balistidae family takes its common name from a set of spines the fish use to deter predators or to “lock” themselves into holes, crevices, and other hiding spots. The system can be "unlocked" by depressing a smaller, “trigger” spine.
Triggerfish tend to be solitary but meet at traditional mating grounds according to timetables governed by moons and tides. The males of many species appear to establish territories on these spawning grounds and prepare seafloor nests that will house tens of thousands of eggs. Females share care of the eggs until they hatch, blowing water on them to keep them well supplied with oxygen. In some species males are known to maintain a harem of female mates.
Triggerfish are infamous for their nasty attitude and this behavior is especially evident around nests, where intruders, from other fish to human divers, are likely to be charged or bitten.
Triggerfish are attractive animals and some species have become too popular for their own good. They are sought for the aquarium trade, which has prompted fishermen to gather even threatened species from the wild. Researchers are working to raise triggerfish in captivity so that wild populations might more likely be left alone.