Platy is a common name for two related species of freshwater fish in the genus Xiphophorus. Both species are livebearers, similar to other fish of the family Poeciliidae, such as the guppy and molly. Platies are native to the east coast of Central America and southern Mexico.
The two species, the southern platyfish and the variatus platy, have been interbred to the point where they are difficult to distinguish. Most platies now sold in aquariums are hybrids of both species.
The southern platyfish (Xiphophorus maculatus) grows to a maximum overall length of 7.0 cm (2.4 in). 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.
The variatus platy (Xiphophorus variatus) grows to a maximum overall length of 7.0 cm (2.8 in). In the wild they are olive in color with black marbling or spots on the side of the caudal peduncle. Large males show blackish blotches on the dorsal fin. Unlike some other members of the genus, X. variatus has no claw at the tip of the fifth anal fin ray. The fourth pectoral ray shows well-developed serrae (i.e. saw-like notches). They typically have 20 to 24 lateral scales, 10 to 12 dorsal rays and two rows of jaw teeth.
This particular fish is widely used in tropical aquaria. There are several different colors of platy developed.
- "Platy, Platies - Xiphophorus maculatus". FishLore.com. Retrieved 2010-07-24.
- "Platies - Moonfish, Variegated Platy, Variatus Platy". Animal-World. Retrieved 2010-07-24.
- Page, Lawrence M.; Burr, Brooks M. (1991). A Field Guide to Freshwater Fishes. New York: Houghton Mifflin. ISBN 0-395-91091-9.