Males br ighter than females with a dar kedge on dorsal, anal, and pelvic fins. Dorsal fin coveredwith high density of black blotches. Male flank bars 8-12, broad with interspaces about equal or slightly narrowerand extend from behind head to tail. Anterior barsfade on belly, posterior ones on caudal peduncle, encirclethe body. Females with less defined bars, more distincton lower body. A mid-flank stripe along the body. Dorsally,head dark grey and head sides densely speckledwith melanophores. Eye bounded by a thin line of darkpigment. Paired fins yellowish or light orange. Pelvic finmargin blackish. Anal fin light cream with a broad,blackish margin. Translucent fins in females. Dorsal andanal fins larger in males. Maximum age 3 years and totallength 45 mm. Type locality water temperature 27ºC,pH=6.7, water brackish, conductivity 11000 μS and dissolvedoxygen 12.3 mg/l. Current slow and no cover. Reproductionin spring with a peak in May. Maturity in firstyear, at 3 cm total length. Absolute fecundity up to 390eggs with a diameter of up to 1.5 mm. Food include algaeand insect larvae.