About Acanthurus nigricans (Linnaeus, 1758)
Acanthurus nigricans has an elongated oval-shaped body, with a steep dorsal head profile and an eye positioned high on the head. It has a small protrusible mouth, with 8 to 28 small teeth on the jaws; these teeth have flattened, notched tips. The dorsal fin is supported by 9 spines and 28 to 31 soft rays, while the anal fin contains 3 spines and 26 to 28 soft rays. The overall body color is bluish-black or black, broken by a large white patch below the eye. A yellow band runs along the base of both the dorsal and anal fins, and this band widens as it approaches the caudal fin. The caudal peduncle has a yellow patch surrounding the spine and its sheath. The caudal fin is white, with a slender yellow submarginal band. This species has a maximum published fork length of 36 cm (14 in). Acanthurus nigricans occurs in the Indian Ocean as far east as the Chagos Islands (British Indian Ocean Territory, central Indian Ocean), Christmas Island, and the Cocos (Keeling) Islands (eastern Indian Ocean). It is more widespread in the Pacific Ocean, where it ranges from the Ryukyu Islands of southern Japan south to the Great Barrier Reef, and extends east across the Pacific to the eastern coasts of Central and South America, between the Gulf of California and Ecuador. This is a benthopelagic fish; adults are found at depths from the surface down to 67 m (220 ft), over hard substrates in clear waters of lagoons and seaward reefs. Juveniles hide among large corals.
