Diagnosis: body short, deep (depth comprised 1.7-2.3 times in fork length) and strongly compressed; head with a typical hump above eyes and a steep frontal profile that is slightly concave in front of eyes; lower jaw prominent; 2 dorsal fins, 1st with 8 spines that are very short in adults, 2nd with 1 spine and 23 or 24 soft rays; anal fin with 2 anterior detached spines (resorbed in adults), followed by 1 spine and 18-20 soft rays; anterior lobes of soft dorsal and anal fins small or indistinct; pelvic fins very short, nearly rudimentary; body (except breast) entirely covered with minute cycloid scales embedded in the skin; lateral line distinctly arched over pectoral fins, with some weak scutes on the straight posterior part; 2 lateral keels at base of caudal fin (Ref. 57392). Silvery with faint dusky opercular spot; juveniles with oval black spot over straight lateral line (Ref. 3197).

Coloration: entirely silvery with bluish reflections that are more pronounced on dorsal half; a blackish spot at upper angle of gill cover; in juveniles, another blackish spot on sides of body, at the inflexion point of the lateral line; fins hyaline (Ref. 57392).