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.
Place of origin:Western Indian Ocean
Red Sea and Gulf of Aden, Arabian Sea. Usually found over open sand and rubble bottom in lagoons or at the base of seaward reefs. Occurs in small groups or forms large, loose aggregations. Similar to Acanthurus nigricaudus and is best distinguished form it by the lack of a black stripe in front of the spine. Length to 40cm.