any plectognath fish of the family Balistidae, of tropical and temperate seas. They have a compressed body with erectile spines in the first dorsal fin
triggerfish in American English
(ˈtrɪgərˌfɪʃ)
nounWord forms: pluralˈtriggerˌfish or ˈtriggerˌfishes
any of various brightly colored tropical fishes (family Balistidae) of the same order (Tetraodontiformes) as puffers, having a prominent first dorsal fin with two or three spines
Word origin
because depression of the second spine of the fin causes the first to snap down