Variable Platyfish

Variable Platyfish, Xiphophorus variatus

Variable Platyfish, Xiphophorus variatus, Golden Morph. Fish caught out of drainage canal in the greater Tampa, Florida area, November 2020. Length:  4.6 cm (1.8 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Variable Platyfish, Xiphophorus variatus, Golden Morph. Fish caught out of drainage canal in the greater Tampa, Florida area, November 2020. Length:  4.6 cm (1.8 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Variable Platyfish, Xiphophorus variatus, Red Morph. Fish caught out of drainage canal in the greater Tampa, Florida area, November 2020. Length:  5.6 cm (2.2 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Variable Platyfish, Xiphophorus variatus, Red Morph. Fish caught within Dickson Azalea Park, Tampa, Florida. September 2018. Length:  5.6 cm (2.2 inches). Catch, photograph and identification courtesy of Ryan Crutchfield, Tampa, Florida.

Variable Platyfish, Xiphophorus variatus, Female. Fish collected with a net out of the Rio de Santiago river basin in the Las Cuevas section of the East Cape of Baja California Sur, December 2017. Length: 6.6 cm (2.6 inches). Catch courtesy of Brad Murakami, Surrey, British Columbia, Canada. Genus identification courtesy of Dan Fuller, International Tuna Commission, La Jolla, California. Species identification courtesy of Dr. John Lyons, Madison, Wisconsin.

Variable Platyfish, Xiphophorus variatus, Male Or Immature Female. Fish collected with a net out of the Rio de Santiago river basin in the Las Cuevas section of the East Cape of Baja California Sur, December 2017. Length: 6.6 cm (2.6 inches). Catch courtesy of Brad Murakami, Surrey, British Columbia, Canada. Genus identification courtesy of Dan Fuller, International Tuna Commission, La Jolla, California. Species identification courtesy of Dr. John Lyons, Madison, Wisconsin.

The Variable Platyfish, Xiphophorus variatus, is a member of the Livebearer or Poeciliidae Family, that is also known as Platy and Moonfish and in Mexico as espada de Valles. Globally, there are twenty-eight species in the genus Xiphophorus, the majority of which are found in Mexican waters, all within the freshwater drainage systems that empty into both the Atlantic and the Pacific Oceans.

The Variable Platyfish has a small, laterally compressed, deep body with a depth that is approximately half the standard length. They vary significantly in color with native fish being pale olive-gray with or without black speckled patches while those raised in captivity are very colorful with various shades of orange, red, yellow, red and black, and black and white. They have a large flattened head, an upturned mouth, and large eyes. They are sexually dimorphic. Males have anal fins with a gonopodium that does not extend to the caudal fin base and is used in reproduction, a third ray with a hook, a pointed caudal fin, and a dorsal fin with 7 to 11 rays. Females have a similar morphology but their anal fins are fan-shaped. They lack the mid-lateral stripe found in other members of the genus.

The Variable Platyfish is non-migratory and found in slow-moving freshwater canals, ditches, and warm springs with aquatic or emergent vegetation with water temperatures between 15°C (59°F) and 25°C (77°F). They reach a maximum of 7.0 cm (2.8 inches) in length. They are omnivores and consume plant detritus, small crustaceans, insects, and annelid worms. They are preyed upon by various pelagic and surface predatory fish as well as numerous seabirds, including herons. Reproduction is ovoviviparous with internal fertilization. Females give birth in twenty-four days to one hundred large fry at a time.

The Variable Platyfish is native to Mexico’s Yucatán Peninsula from Tamaulipas to Belize, however, they have a rapidly expanding global range attributed to farm escapes and aquarium releases; they are now present in at least 18 countries and are found in Africa, Asia, the Caribbean, Central America, North America, and South America in tropical and subtropical environments. They are highly invasive and highly adaptive being found in a wide variety of habitats including warm springs, weedy canals, and ditches and have caused significant impact on native fish by competing for food sources.

The Variable Platyfish is most likely confused with the Southern Platyfish, Xiphophorus maculatus (more lateral scales; more dorsal rays) and the Green Swordtail, Xiphophorus hellerii (sword appendage on lower rays of caudal fin).

From a conservation perspective the Variable Platyfish is currently considered to be of Least Concern with stable, widely distributed populations. They are a popular aquarium fish with Platys being the third most imported ornamental species into the United States. They are very peaceful, non-aggressive, and easy to maintain being well suited to a communal aquarium, however some of their young are eaten by the adults or other inhabitants of these aquariums. In captivity, they reach maturity in three to four months and breed continually. They have been utilized scientifically in genetic research. They are also known to become pests as they are highly invasive.