Family: POECILIIDAE, Livebearers, Toothcarps
male with long sex organ
Poeciliids are small fishes (4-20 cm), elongate to moderately deep bodied; front nostril not tubular; covering of eye not continuous with skin of head; fins without spines; 1 dorsal fin, at rear of body, its origin over (female) or behind (male) anal fin origin; 3rd anal ray unbranched; pectoral fins high on the sides of the body; pelvic fins originate behind pectoral fin base, under pectoral rays; males of most species have a gonopodium, which facilitates internal fertilization, an elongated structure composed primarily from the 3rd-5th anal rays; lateral line reduced to a series of individual pits along side of body; head and body scaled; scales smooth, large.
This family includes many popular aquarium fishes, including the world famous Guppy (Poecilia reticulata), swordtails, platies, and mollies. They are inhabitants of fresh and brackish waters of low-lying areas of tropical and temperate in American"s seas. As the common name suggests, almost all the members of this family give birth to live young.
The family contains about 40 genera with at least 300 species. Five members of one genus that commonly occur in brackish estuaries in our region are treated here.