Diagnosis: Body slender, its depth 18 to 30% of standard length; presence of two fleshy outgrowths on the hind margin of the gill opening; sharp belly with keeled scutes, 16-19 pre-pelvic and 12-14 post-pelvic scutes (Ref. 188, 3259). The presence of elongate wing-like scales underneath the normal paired pre-dorsal scales separate it from all other species except the two Australian species with prominent black spots on the flank, Herklotsichthys koningsbergeri and Herklotsichthys Species A, and the unspotted Herklotsichthys Species B, which has dusky tips to dorsal and caudal fins and more lower gill rakers, 36-42 vs. 33-36 in H. quadrimaculatus (Ref. 188). Flank silvery with an electric blue line preceded by two orange spots (Ref. 188).

Description: Body fusiform, moderately slender; depth of body 3.1-3.9 in standard length (Ref. 3107, 90102). Top of head with few, fronto-parietal striae, about 4-7 striae on each side (Ref. 3259). Lower portion of paddle-shaped second supramaxilla longer than upper; gill opening with two fleshy outgrowths; no prominent ridges of teeth on roof of mouth (Ref. 3107, 3259). Lower gill rakers 28-37; upper gill rakers 11-16; total gill rakers 40-50 (Ref. 3259, 122993). Dorsal fin with 3-5 unbranched and 13-16 branched rays; anal fin with 2-4 unbranched and 13-17 branched rays; pectoral fin with 1 unbranched and 13-16 branched rays; pelvic fin with 1 unbranched and 7 branched rays (Ref. 3259, 122993). Longitudinal scale series 38-45; broad wing-like scales almost hidden beneath the overlapping pre-dorsal scales (Ref. 3107, 3259, 30573, 122993). Sharp belly, with keeled scutes; total ventral scutes 30-32, with 16-19 pre-pelvic and 12-14 post-pelvic scutes (Ref. 3259, 90102, 122993).

Colouration: Back blue-green without spots, flanks silvery with two orange spots behind gill opening in life and a blue midlateral band (Ref. 188, 3107, 3259).