arshba.ru

Montezuma Swordtail, lat. Xiphophorus montezumae (Xiphophorus montezumae)


Order: Cyprinodontiformes;
Family: Poeciliidae;
Genus: Xiphophorus;
Species and synonyms: Green swordtail (Xiphophorus hellerii, Xiphophorus helleri, Green Swordtail, Swordtail).

GBIF: Xiphophorus hellerii Heckel, 1848

Green swordtail (lat. Xiphophorus hellerii) is a species of livebearing ray-finned fish from the order Cyprinodontiformes, family Poeciliidae, genus Xiphophorus. One of the most popular and recognizable aquarium fish in the world.

Distribution. The natural range of Xiphophorus hellerii covers freshwater and brackish waters of Central America: from southern Mexico (Veracruz, Tabasco) to Guatemala, Belize and northwestern Honduras. It inhabits slow-flowing rivers, canals, ponds and lakes with dense aquatic vegetation. Due to its popularity in aquaristics, the species has been introduced to tropical regions worldwide, including the USA (Florida, Texas), Australia and some Pacific islands.

Care requirements. The green swordtail is one of the most undemanding aquarium fish. For keeping a small group (1 male and 3–4 females), an aquarium of 80 liters or more is recommended. Optimal water parameters: temperature 22–28°C, hardness 10–25 dGH, pH 7.0–8.5. Filtration, aeration and weekly water changes of 20–25% are required. Swordtails are omnivorous: they accept dry flakes, pellets, live and frozen foods (bloodworms, brine shrimp, tubifex, daphnia). To maintain color brightness, it is desirable to use foods with carotenoids. Males reach up to 10–12 cm in length (excluding the sword), females — up to 12–14 cm. Females are larger than males, with a more rounded abdomen and without the characteristic sword-like extension on the caudal fin. Lifespan with good care is 3–5 years.

Green swordtails are livebearers with internal fertilization. They reach sexual maturity at 6–8 months of age. Pregnancy lasts about 4–6 weeks, the female gives birth to 30–80 fry (depending on size and age). Adults may eat the fry, so it is recommended to use dense plant thickets for fry to hide in, or to remove the female to a separate breeding tank before giving birth. Fry are fed brine shrimp nauplii, microworms and fine dry food. The young grow quickly and with good feeding reach sexual maturity by 6 months.

Xiphophorus hellerii has characteristic sexual dimorphism: in males, the lower rays of the caudal fin are elongated into a long sword-like process (hence the genus name — "swordtail"), which can reach a length equal to the body length. The coloration of the wild form is olive-green with a reddish-brown stripe along the body and a yellow or red spot at the base of the tail. Thanks to many years of selection, numerous color variations have been developed: red, yellow (lemon), black, calico, tiger, albino, as well as forms with different fin shapes (veiltail, lyretail, flagtail). Breeders have also created hybrids with other species of the genus Xiphophorus.

In the wild, swordtails feed on aquatic invertebrates, insect larvae and plant material. They are active, mobile, and prefer to stay in the upper and middle water layers. Males may show aggression towards each other, so it is recommended to keep one male with several females, or a group of females without males if population control is needed. Swordtails coexist well with most peaceful fish species of comparable size, but may nip the veil fins of slower fish.