40, mostly cranky, species
Triggerfish, of the family Balistadae, are found in warm waters around the world. While the largest of the species, the stone triggerfish, can grow to over three feet in length, most range between eight and 20 inches. Regardless of species, triggerfish are well known for their displays of temper—they can be particularly territorial around nesting sites, charging at and even biting intruders!
Unlike other fish that use their whole bodies to swim, triggerfish usually get around using only their top and bottom fins. That makes them highly maneuverable—they can swim backwards and forwards, or hover like a UFO. But when they feel the need for speed, their broom-like tails give them a quick thrust and away they go!
These fish get their names the fact that their first three dorsal fins are adapted in such a way that the first one, which is very strong, can be braced into an upright position by the second, allowing it to lock itself into holes. When they want to come back out, the second spine acts as a “trigger” to unlock the first. Triggerfish use this adaptation when feeling threatened—or when going to sleep. Once they’re "triggered in," it's nearly impossible to get them out.
No tooth fairy for triggerfish
The strong, sharp teeth of triggerfish grow throughout their lives, just like human fingernails. They need to chew hard things—for instance clam shells—to wear down their teeth and keep things under control, choppers-wise.
Too pretty for their own good?
Because of their beauty, the charming way they swim, and their innate toughness, triggerfish are popular for home aquaria—too popular. To meet global demand, fishermen are gathering even threatened species from the ocean. Researchers are trying to raise the fish in captivity, to help take pressure off of wild populations.