Species: Poecilia koperi, Olomina molly, the Olomina

Poecilia koperi Poeser, 2003

Olomina

Head stout, body relatively deep, moderately compressed at rear; head depressed; front nostril not tubular; covering of eye not continuous with skin of head; mouth small, at front, slightly oblique, lower jaw slightly projecting, top jaw protractile; jaw teeth consist of an outer row of large backward curved teeth with expanded tips, and several rows of small pointed teeth, inner row 1-pointed; 1 dorsal fin with short base, at rear of body, 8 (rarely 7) rays, fin long, reaches tail base; pelvic origin well behind pectoral base, near anal fin; tip of pelvic fin of males swollen, elongate;  pectorals high on flank, 14 or more rays, 5th ray not scalloped in male; anal fin 8 (rarely 9) rays, origin under (female) or a little behind (male) dorsal fin origin; 3rd anal ray unbranched; anal fin modified in male to form an elongate sex organ, that organ short & with a straight tip that has small spines (not visible externally) and a long fleshy palp; tail base relatively narrow; tail fin rounded, without elongate sword; scales smooth and relatively large; 25-26 lateral scales, 16 around tail base.

Maracaibo area: Male - body scales with dark edges; ~10 dark bars on rear of body and tail base; tail fin base covered with irregularly pigmented scales; tail fin with longitudinal spots; dorsal fin with a large dark blotch on basal ½ of fin, dark spots outside that. Female - body colored like male, but with body bars less evident; fins without spots. East of Paraguana Peninsula; body with 2-3 horizontal rows of spots, less conspicuous below; tail fin with spots on membranes, dorsal fin spotted on membranes.

Reaches 10 cm?

Fresh and brackish coastal waters.

Depth range: 0-1 m.

Venezuela.