Triggerfishes Pufferfishes and Relatives: Tetraodontiformes

Physical characteristics: Clown triggerfish have an oval body that is narrow from side to side. The pelvic fins are fused into a single spine. There are three spines in the front dorsal fin. The second spine is the trigger for locking the first spine into an upright position. Clown triggerfish grow to a length of about 20 inches (50 centimeters). The bright color pattern of clown triggerfish gives the fish their name. The black background is covered by large white ovals on the bottom half and yellow rings on the upper half of the fish. The breast is white, and there is a white band below the eyes. The tail is white, and there is a pattern of black, white, black on the tail fin. Starting at the tip, the mouth colors are a wide band of yellow or orangish yellow, a narrow band of black, and a thin yellow stripe. The bases of the anal fin and the rear dorsal fin are light yellow. The anal (AY-nuhl) fin is the one along the midline of the belly. The dorsal (DOOR-suhl) fin is the one along the midline of the back. The pectoral (PECK-ter-uhl) fins correspond to the front legs and the pelvic fins to the rear legs of four-footed animals.

Clown triggerfish use their locking first dorsal spine as a defense against predators. (©Fred McConnaughey/Photo Researchers, Inc. Reproduced by permission.)

Geographic range: Clown triggerfish live in the Indian Ocean and the western part of the Pacific Ocean.

Habitat: Clown triggerfish live mainly on reefs.

Diet: Clown triggerfish eat bottom-dwelling invertebrates.

Behavior and reproduction: Clown triggerfish use their locking first dorsal spine as a defense against predators (PREH-duh-ters), or animals that hunt and kill other animals for food. These fish live alone and aggressively defend their territory. They spawn in pairs, laying eggs in a nest on the bottom and defending it. The larvae drift in the water.

Clown triggerfish and people: Clown triggerfish are used in aquariums.

Conservation status: Clown triggerfish are not threatened or endangered. ∎