Species: Poecilia sphenops, Mexican Molly

Poecilia sphenops Valenciennes in Cuvier & Valenciennes, 1846

Mexican Molly

Head and body moderately robust, 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 band of teeth mostly with 3 points; 1 dorsal fin with short base, at rear of body, behind pelvic base, 9-10 rays; pelvic origin well behind pectoral base, near anal fin; tip of pelvic fin of males swollen, elongate; pectorals high on flank, 5th ray not scalloped in male; anal fin 9, origin a little behind (female) to well before (male) dorsal fin origin; 3rd anal ray unbranched; anal fin modified in male to form an elongate sex organ, that organ relatively short, with straight tip that has small spines & a fleshy palp; tail base relatively narrow; tail fin rounded, without elongate sword; no lateral line pores on snout; scales smooth and relatively large, 26-27 lateral scales, 18 around tail base.

Male: Pale grey brown above, silvery white below; rows of orange dots along scales on upper ¾ of body; dorsal fin with yellowish to reddish margin, and 2-4 rows of blackish dots on membranes of inner 2/3 of the fin; tail fin with yellow to reddish wash, plus several vertical rows of blackish dots. Female: pale grey-brown, with dark spots, silvery white on belly and cheeks; fins clear except for a row of dark dots along dorsal fin.

Reaches 6 cm.

Fresh to brackish water.

Depth range: 0-3 m.

The S Gulf of Mexico, Belize to Colombia