Achilles Tang

Acanthurus achilles has an elongated oval-shaped body with a steep dorsal profile to the head. The small, protrusible mouth is positioned low on the head with between 8 and 28 teeth fixed on each jaw, each having a flattened, serrated tip. The dorsal fin is supported by 9 spines and between 29 and 33 soft rays while the anal fin contains 3 spines and 26 to 29 soft rays. There is a single mobile spine on each side of the caudal peduncle which folds down into a slit. The caudal fin is concave. The overall color is bluish-black with an irregular oval orange blotch near the rear of the body and a white bar on the operculum. The caudal fin is predominantly orange, but its posterior margin is white. There is a pale blue ring around just inside the snout tip. This species reaches a maximum total length of 24 cm (9.4 in).

Acanthurus achilles is found in various reefs of Oceania, up to the islands of Hawaii and Pitcairn. It is also, although less commonly, found in the Mariana Islands and even some reefs in southern Mexico and Guatemala. It is a benthopelagic species which inhabits the clear waters on the seaward side of reefs.

The choice of the specific name of this species, achilles, was not explained by Shaw. It is thought that the name refers to Achilles, the mythical hero of the Trojan War, and that it alludes to the sharp bony plates on the caudal peduncle.