Appearance
Acanthurus dussumieri is a deep-bodied, laterally-compressed oval fish with a maximum length of 54 cm (21 in). The head is small, with slightly prominent eyes, a small beak-like mouth and inflated, pale lips. The body is smooth, being covered with small scales, but like other surgeon-fish, it has a pair of scalpel-like, modified scales on the caudal peduncle; these can either be folded flat or raised in defence. Both dorsal and anal fins are long, and the pectoral fins are used for locomotion and balance. The throat is blue, and the rest of the head has a dense network of blue or grey-blue lines, which are wider than the fine grey-blue, wavy, longitudinal lines on the pale brownish body. There is a broad orange bar above the eyes and a narrow orange band borders the base of the dorsal fin. The scalpel-like scales are white and are surrounded by a black blotch.

