Fish

Powderblue Surgeonfish

Acanthurus leucosternon

A vivid powder-blue surgeonfish with a yellow dorsal and white breast, grazing KZN's warm coral reefs.

Also known as powder-blue surgeon, powderblue tang, unicornfish, whitebreast surgeonfish

Powderblue Surgeonfish
Photo: Nikolai Vladimirov · CC BY-NC 4.0
Typical size
Commonly 20-25 cm
Habitat
Warm coral and rocky reefs
Depth
Surface to about 25 m

The powderblue surgeonfish is one of the most striking reef fish in South African waters: a compact, disc-shaped body of clear powder blue, set off by a black face mask, a bright yellow dorsal fin and a white throat and breast. Like all surgeonfish it carries a sharp, scalpel-like spine on each side of the tail base, which gives the family its name.

It occurs on the warm coral and rocky reefs of northern KwaZulu-Natal, where it grazes algae from the reef, often in loose aggregations that move across the bottom. Divers should admire it without handling, as the caudal spines can inflict a nasty cut if the fish is grabbed; it is otherwise a peaceful grazer.