The southern platyfish, common platy, or moonfish (Xiphophorus maculatus) is a species of freshwater fish in family Poeciliidae of order Cyprinodontiformes. A live-bearer, it is closely related to the green swordtail (X. hellerii) and can interbreed with it. It is native to an area of North and Central America stretching from Veracruz, Mexico, to northern Belize. The southern platyfish grows to a maximum overall length of . Sexual dimorphism is slight, the male's caudal fin being more pointed. The anal fin of the male fish has evolved into a gonopodium, a stick-shaped organ used for reproduction. The female southern platyfish's anal fin is fan shaped. Wild varieties are drab in coloration, lacking the distinctive dark lateral line common to many Xiphophorus species. X. maculatus prefers slow-moving waters of canals, ditches, and warm springs. Omnivorous, its diet includes both plants and small crustaceans, insects, and annelid worms. Breeders have developed a multitude of color varieties (e.g. orange, red, yellow, red/black, and black/white) which are common aquarium fish for hobbyists. The southern platyfish is commonly known simply as the platy (pl. platys or platies), from the fish's original generic name, Platypoecilus. Nonindigenous occurrences This species has been recorded from Orange County, California, near Westminster; near a fish farm in Conejos County and the South Platte drainage, Colorado; several counties in Florida; Hawaii; an unnamed tributary to Big Branch Bayou in Lacombe, Louisiana; Beaverhead Rock Pond (Madison County), Montana; Clark County, Nevada; and Texas. It has also been collected in the Loiza drainage near Loiza Reservoir, Quebrada Honda, and Rio Abajo Forest Station north of Utuado in Puerto Rico. The southern platyfish has been released probably due to fish farm or aquarium releases. Specimens in Louisiana were collected near a tropical fish farm. Southern platies, and other introduced poeciliids, have been implicated in the decline of native damselflies on Oahu, Hawaii. Often the distributions of the damselflies and introduced fishes were found to be mutually exclusive, probably resulting from competition for limited insect food. In the aquarium Platies are easy to keep and well suited to a community aquarium. They prefer water with a 7.0–8.0 pH, a water hardness of 9.0–19.0 dGH, and a temperature range of . In captivity, they reach maturity in three to four months, and breed readily, the females giving birth to about 20–40 young at a time. Often young are eaten by the adults or other inhabitants of