Elongate surgeonfish
(Acanthurus mata)

Acanthurus mata is a medium sized fish that can reach a maximum size of 50 centimetres (20 in) length.

The body has an oval shape and is compressed laterally. Like other surgeonfishes, Acanthurus mata swims with its pectoral fins. The caudal fin has a crescent shape. The mouth is small and pointed.

Its body is streaked with horizontal bluish lines on a brown background color although over time it is able to change colour to become grey-blue overall. A longitudinal yellow stripe runs across the eye and splits in two lines extending anterior the eye. The superior lip is also yellow. The dorsal and anal fin are bluish with a yellow reflection, with the base of the latter underlined by a fine black line. A sharp erectile spine (comparable to a scalpel, thus the species name) at the base of the tail is a defensive weapon.

Acanthurus mata has a wide distribution in tropical waters going from the west part of the Indian Ocean to the archipelagos in the middle of Pacific Ocean. It is found from the Red Sea and Gulf of Oman, south to Natal, eastwards to Society and Marquesan Islands, northwards to southern Japan, southwards to New South Wales and New Caledonia. Juveniles occur as far south as Sydney (R. Myers pers. comm. 2010). It is reported from Western Australia (Allen and Swainston 1988), south to Shark Bay. It is not known to occur from the Hawaiian Islands, Pitcairn Islands and Rapa (Randall 2001a). In 2021, the species was recently recorded off the Galápagos Islands in the Tropical Eastern Pacific.