Diagnosis: more slender and elongate than congenerics, with smaller head, eyes and mouth; ripe males with yellow-white dorsal "blaze" (Ref. 55949).

Description: eye size variable, but diameter usually less than snout length; small, upwardly-angled protrusible mouth; long, closely-packed gill-rakers (Ref. 55949).

Coloration: body silvery, countershaded; live females and non-breeding males often exhibit a bright metallic purple sheen; males in breeding dress are dark grey to black, with a bright yellow-white dorsal blaze; maturing males dark grey dorsally, silver-grey on the flanks and pale ventrally; dorsal fin grey-white or yellow, sometimes only on the distal part of the fin, the lower part being dark grey or black; dorsal blaze white or yellow, sometimes peppered with black spots, extending from the snout to the dorsal fin, and sometimes all along the upper body surface to the caudal peduncle; caudal fin grey, sometimes with yellowish upper and lower borders; pelvic and anal fins grey, white or yellow; 1-2 large, pale eggspots on anal fin (Ref. 55949).