Variable Platyfish

The variable platyfish (Xiphophorus variatus) is a small, hardy livebearer native to rivers and springs of northeastern Mexico, closely related to the southern platyfish but distinguished by a more elongated body and remarkable natural variation in color and pattern between populations. As its name suggests, wild individuals display an unusually wide range of yellow, orange, black, and red markings even within a single locality, a trait that made the species especially attractive to early aquarium breeders. This natural diversity has been further developed through selective breeding into strains such as the sunset platy, marigold platy, and calico platy. Variable platyfish are hardy, easy to breed, and tolerate a broader temperature range than many other livebearers, including cooler water, making them a versatile addition to community aquariums.

• Body shape: More elongated and slightly less deep-bodied than the southern platyfish
• Coloration: Naturally highly variable, with combinations of yellow, orange, black, and red spots or stripes even within wild populations
• Fins: Rounded dorsal fin and fan-shaped caudal fin, without a sword
• Size: Slightly larger on average than southern platyfish
• Sexual dimorphism: Males have a gonopodium and are generally smaller than females

Look-alikes: Southern platyfish (Xiphophorus maculatus) are shorter, deeper-bodied, and less variably patterned in the wild; swordtails grow a distinct tail sword absent in both platy species.

Variable platyfish are native to clear, moderately flowing rivers, streams, and spring systems in the states of Veracruz, San Luis Potosí, and Tamaulipas in northeastern Mexico. They inhabit a slightly cooler and more temperate range than the southern platyfish, tolerating temperature drops that would stress more tropical livebearers, and are often found in vegetated shallows with sandy or gravel substrate. This adaptability to cooler conditions has allowed variable platyfish to establish feral populations in temperate spring-fed waters outside their native range, including in the southern United States, where constant-temperature spring water allows them to persist year-round.

Variable platyfish are peaceful, active shoaling fish that spend the day foraging along the bottom and among vegetation for algae, biofilm, and small invertebrates. They are undemanding in captivity and adapt to a wide range of foods and water conditions. Reproduction follows the typical livebearer pattern: males court females with fin displays and repeated approaches before mating via a gonopodium, and females give birth to broods of 20 to 80 free-swimming fry roughly every 4 weeks, with the ability to store sperm for multiple broods. Fry receive no parental care and seek cover among plants to avoid being eaten by adults. The species is generally non-aggressive and mixes well in community aquariums.