Lake Cuitzeo Jeweled Splitfin

Lake Cuitzeo Jeweled Splitfin, Xenotoca cf. variata

The Lake Cuitzeo Jeweled Splitfin, Xenotoca cf. variata, whose common Spanish name is pintada de Cuitzeo, is a member of the Splitfin or Goodeidae Family, known collectively as mexclapiques in Mexico. Globally, there are five formally recognized members in the genus Xenotoca, all from the freshwater systems of central mainland Mexico. This fish has not as yet been fully characterized but should be very similar in morphology and behavioral patterns to the Jeweled Splitfin, Xenotoca variata.

The Lake Cuitzeo Jeweled Splitfins have elongated and narrow bodies with a pointed snout and an elongated caudal peduncle. They are sexually dimorphic. Males are grayish-green dorsally and white to yellow ventrally with dark fins, a yellow margin on their caudal fin, and large reflecting greenish to yellowish scales on their sides. Females are grayish-brown and slightly darker dorsally with a dusky head and dark spots of various sizes that form a mid-lateral stripe.

The Lake Cuitzeo Jeweled Splitfins are found demersal at depths up to 5 feet in springs with clear water and an abundance of algae covered rocks and submerged vegetation, in open murky water, or close to shore near reeds over gravel, muddy and sandy bottoms with slight current flows and consistent year-round temperatures between 20oC (70oF) and 30oC (85oF). Their maximum length has not yet been reported. They are assumed to be omnivores that feed on algae, detritus, fish fry, water insects, and other small invertebrates. Reproduction is assumed to be viviparous and involve internal fertilization followed by a short gestation period with each female giving birth to young able to survive on their own. They practice cannibalism on a small scale.

In Mexican waters the Lake Cuitzeo Jeweled Splitfins are found in the Río de Morella drainage including Lake Cuitzeo and the Huingo, La Maiza, Peesca de Cointzio, and Zinapécuaro Springs in the State of Michoacán within the Central Plateau west of Mexico City.

The Lake Cuitzeo Jeweled Splitfins should be considered Near Threatened from a conservation perspective as their local water habitat has experienced a staggering amount of degradation during the 20th century and they are heavily preyed upon by various birds and recently introduced non-native fish including Black Bass, Guppies, Largemouth Bass, Sunfish, and Tilapia.

Lake Cuitzeo Jeweled Splitfin, Xenotoca cf. variata, Female. Fish caught in a small lake within the Mexican Plateau in west-central Mexico, Michoacán, February 2017. Length: 5.7 cm (2.2 inches). Catch, photo, and identification courtesy of Ryan Crutchfield, Tampa, FL.

Lake Cuitzeo Jeweled Splitfin, Xenotoca cf. variata, Female. Fish caught in a small lake within the Mexican Plateau in west-central Mexico, Michoacán, February 2017. Length: 8.5 cm (3.3 inches). Catch, photo, and identification courtesy of Ben Cantrell, Peoria, IL.

Lake Cuitzeo Jeweled Splitfin, Xenotoca cf. variata, Male. Fish caught in a small lake within the Mexican Plateau in west-central Mexico, Michoacán, February 2017. Length: 6.5 cm (2.6 inches). Catch, photo, and identification courtesy of Ben Cantrell, Peoria, IL.