A fish (family Balistidae) that has a deep, oval, compressed body, a large head, a small, strong mouth, and eyes on top of the head. The dorsal fin consists of three spines, which are normally held in a groove. The first spine is the longest and strongest and can be locked in a vertical position by erecting the second spine, and unlocked only by depressing the second spine (the ‘trigger’). Triggerfish are slow-moving bottom-dwellers, feeding on invertebrates, fish, or algae. There are 12 genera and about 40 species found worldwide in tropical and subtropical waters.