Genus: Heterandria, Least Killifish, Least Killifishes

HETERANDRIA

LEAST KILLIFISHES

Head and body moderately slender to moderately robust, moderately compressed at rear, upper profile slightly convex; head depressed; front nostril not tubular; cover of eye not continuous with head skin; snout blunt, shorter than eye; mouth very small, opens at front, oblique, lower jaw slightly projecting, top jaw protractile; jaw teeth consist of an outer row of large compressed teeth, and 2 inner rows of small pointed teeth; 1 dorsal fin with short base, 6-18, at rear of body; dorsal fin origin over ~ mid anal fin in female, well behind anal fin of male; pelvic origin well behind pectoral base, near anal fin, tips of male fins like that of female, not swollen; pectorals high on flank, 5th ray not scalloped in male; 3rd anal ray unbranched; anal fin modified in male to form an elongate sex organ, tip of that organ curved slightly downwards, ends with a slight to distinct down-curved hook, no fleshy palp; tail base relatively narrow; tail fin  rounded; scales smooth and relatively large.

A genus of freshwater fishes with 8 species, found from the southern US to Central America; 1 species enters brackish water in our area.