This species is distinguished by the following characters: D VI (rarely V or VII),26-29(modally 27); A II,27-30 (rarely 27 or 30); pectoral rays usually 17; body depths of adults 2.6-3.0 in SL; head dorsal profile sloping and smoothly convex (forehead no horn nor protuberances); two large peduncular plates, the keels with forward-projecting points in adults; caudal fin emaginate in young and truncate in adults; body brown to bluish gray, ventral half yellowish gray to yellow, the demarcation along middle of side often abrupt and irregular; edge of opercle and preopercle usually with a dark brown band; margin of lower lip broadly white with upper surface of tongue black in adults; gill rakers are blackish basally; blue caudal fin with a broad, brownish yellow, posterior border which narrows toward corners of fin; it is capable of changing overall into light grayish blue, as when at a cleaning station; when in courtship the males quickly display a broad, bluish white zone on the nape and anterior part of the body , followed by narrow bars of the same color that extend onto lower side (Ref. 54980).

Description: Characterized further by yellow forehead; pelvic fins yellow; caudal peduncle with pair of bony plates, each with sharp forward projecting keel; large adult male with prolonged filaments on caudal fin lobes; greatest depth of body 2.2-2.7 in SL (Ref. 90102).