» For the genus of butterflies commonly known as swordtails, see Graphium. The Green swordtail (Xiphophorus hellerii) is a species of freshwater fish in family Poeciliidae of order Cyprinodontiformes. A live-bearer, it's closely related to the southern platyfish or "platy" (X. maculatus) and can interbreed with it. It is native to an area of North and Central America stretching from Veracruz, Mexico, to northwestern Honduras. The male green swordtail grows to a maximum overall length of 14cm (5… (More on Swordtail)