Dusky Surgeonfish

Acanthurus nigrofuscus has been recorded growing up to a total length of 21 cm (8.3 in). It has 9 spines and between 24 and 27 soft rays supporting its dorsal fin while the anal fin is supported by 3 spines and 22 to 24 soft rays. The dorsal profile of the head his slightly humped.

The overall colour varies from brown to purplish to bluish-brown marked with small orange spots on the head and breast. There are small black spots at the base of both the dorsal and anal fins, these fins have a pale blue margin. The spine on the caudal peduncle is contained within a patch of black pigment. There may or may not be sinuous horizontal lines of small blue dots.

Acanthurus nigrofuscus has a wide Indo-Pacific distribution from the coast of eastern Africa as far north as the Levantine Red Sea coast and south as far as far south as the Aliwal Shoal in South Africa, across the Indian Ocean and into the Indian Ocean as far east as and the Pitcairn Islands and Hawaii, north as far as southern Japan and south as far as New South Wales.

This is a numerous and common surgeonfish that is found in small schools on sheltered coral and rocky reefs, frequently around isolated rocky reefs at depths down to 25 m (82 ft).