Trigger Fish

trigger fish the common name for a larger number of species in the family Balistidae, notably Balistes capriscus. They may also be called leatherjackets, in allusion to their thick and tough skins. The ‘trigger’ in the main name is a little spine on the back, just behind the solitary dorsal spine (and in fact representing a rudimentary second dorsal spine). This ‘trigger’ can be used to lock the dorsal spine in an upright position.