This species is distinguished from its congeners by the following set of characters: dorsal rays VI + I,8-10 (rarely 8); anal rays I,8-10 (rarely 10); pectoral rays 13-17 (usually 15); first dorsal spine of male produced into elongate filament; absence of pelvic frenum; absence of cephalic sensory canals and associated pores; total longitudinal scales 14-22 (mean 17), including 3-6 (mean 4.6) scales immediately behind pectoral fin and 10-16 12.7) on posterior portion of body, main mass of body scales extending forward from caudal-fin base to about level of sixth segmented dorsal fin ray; colour in alcohol yellowish white with seven widely spaced small brown spots or horizontally elongate streaks in mid-lateral row on side of body, pair of curved dark markings on caudal-fin base, triangular dark mark below eye, large dark blotch on anterior opercle, oblique dark band on lower pectoral-fin base and extending under opercle, row of 10 dark spots along dorsal midline from first dorsal fin to caudal-fin base with corresponding row of smaller spots on either side of midline, and five elongate dark streaks on ventral midline from base of anterior anal-fin rays to middle of caudal peduncle; and live male and female individuals capable of 'switching on' bright nuptial/territorial colour patterns (only males possess this ability in most other congenerics) (Ref. 138626).