Triggerfish any of several species of tropical reef fishes with
laterally compressed bodies, heavy scales, and tough skins. They are
named for the mechanism of the three spines of the dorsal fin: when the
fish is alarmed the first of these spines is locked upright by the
second and drops only when the latter is pressed like a trigger. The
function of this reaction is to lock the fish firmly in a mass of
coral; when attacked, the fish dives into the coral and erects the
spine, releasing it only when the danger has passed. Trigger fishes have
powerful, chisel like teeth adapted for cracking the coral
15"-17"