This species is distinguished by the following characters: body moderately deep and compressed, its depth 2.6 to 3.2 times in standard length (SL); dorsal profile of body uniformly convex, without any bony horn-like projection or protuberance anteriorly on head; mouth small; incisiform teeth very small, somewhat pointed, finely serrate on edges, as many as 80 in upper jaw and 100 in lower jaw of large adults; continuous unnotched D VI (rarely V or VII),26-29; A II,27-30; pectoral-fin rays 17-18 (usually 17); pelvic fins I,3; caudal fin slightly emarginate in young, becoming truncate in adults; caudal peduncle slender, subcylindrical, with a pair of bony plates on each side that develop large sharp antrorse keels with age; body colour dark brownish grey, shading ventrally to yellowish (life colour may vary from dark brown to light blue-grey); edge of operculum and preopercle usually dark brown; dorsal and anal fins yellowish with faint diagonal brown bands and a blue margin; tongue black at lengths of 25 cm or more (Ref. 9808).