The common name "surgeonfish" is derived from a characteristic that clearly distinguishes Acanthuridae from other fish families: the spines or "scalpels" on the caudal peduncle, one or more on each side. Based primarily on differences in this characteristic, the family can be divided into three subfamilies: The Acanthurinae, in which the peduncular spine rests in a groove and can be erected in defence during the fights, the Nasinae and Prionurinae in which the peduncular feature is arranged as one or more fixed blades on each side, that are sharp and elongate with age.
Red Sea and Arabian Sea, ranging to Sri Lanka. Doubtfully reported in the Maldives. Occurs on rubble reefs to about 20m depth. Adults are usually either in pairs or schools. Small juveniles secretive amongst large corals. This species is readily identified by its bright colouration and shape . Length to 25cm