ACANTHURIDAE Surgeonfishes By Hisashi Imamura Acanthurus bariene Acanthurus leucosternon Acanthurus lineatus Acanthurus mata Acanthurus tennenti Acanthurus thompsoni Acanthurus triostegus Acanthurus xanthopterus Ctenochaetus binotatus Ctenochaetus striatus Ctenochaetus truncatus Naso elegans Naso hexacanthus Naso thynnoides Naso vlamingii Zebrasoma desjardinii Zebrasoma scopas High-bodied, compressed fishes (size to about 75 cm) with very small ctenoid scales. Eye high on head. Mouth small, terminal; premaxilla not protractile. Small close-set teeth on jaws; no teeth on roof of mouth. Dorsal fin continuous with IV-IX spines and 19-33 soft rays. Anal fin with II or III spines and 18-28 soft rays. Caudal fin emarginated to lunate, with 16 principal rays. Pectoral fin with 14-18 rays. Pelvic fin with 1 spine and 3 or 5 soft rays. Side of caudal peduncle with sharp spine(s). Color: usually predominately brown to gray, but some species very colorful. Similar family occurring in the area. Siganidae: pelvic fin with 2 spines and 3 soft rays between them; dorsal fin with 13 spines; anal fin with 7 spines. Zanclidae: snout protruding; premaxilla protractile; dorsal fin with a long filament from 3rd spine; no spine or keels on caudal peduncle. Remarks. Acanthurids occur on coral reefs or over rocky substrata, generally at depths less than 100 m. It is divisible into 3 subfamilies: the Acanthurinae, Prionurinae and Nasinae.