Goldrim Surgeonfish

Acanthurus nigricans

The goldrim surgeonfish (Acanthurus nigricans), also known as the whitecheek surgeonfish, is a medium-sized tang reaching about 21 cm in length. It has a dark brownish-black body with a distinctive white band below the eye, a yellow rim on the dorsal and anal fins, and a white-edged caudal peduncle spine typical of surgeonfish. The tail fin is dark with a yellow or gold submarginal band. This species is found throughout the central and western Pacific, from Christmas Island to Hawaii, Pitcairn, and the Marquesas. It inhabits coral reefs and rocky substrates, typically at depths of 1-20 meters, where it grazes on filamentous and small fleshy algae. It is usually seen singly or in small groups, moving methodically across the reef as it feeds. Like other surgeonfish, it possesses a sharp, scalpel-like spine at the base of the tail that can be erected for defense against predators or during territorial disputes. Its bold coloration and consistent presence on reef flats make it a regular sighting for divers across its range.