The scientific name of the fish is (Heterandria formosa Agassiz, 1853 Poeciliidae). It is viviparous, and in size - one of the smallest fish in the world.
The female is 3.5 cm long, and the male is smaller, only 2 cm. Under natural conditions, this small fish lives in North Carolina and Florida.
The distribution of live-bearing fish on our planet is currently very poorly studied, because many species have appeared in nature, thanks to artificial selection, consciously carried out by man. They live even in thermal springs, in temperate zones.Formosa (Heterandria formosa).
A distinctive feature of the appearance of viviparous is a pronounced sexual dimorphism, that is, differences in gender, as well as a variety of methods of reproduction. And the fish are born the same in appearance and sexual characteristics appear in the process of further development. Only with age can the fish be divided into males and females.Formosa fish is good for breeding in a home aquarium.
A characteristic feature of males are well-developed fins. In fish of many species, the third, fourth and fifth rays of the anal fin are converted into a special mating organ - gonopodia. The remaining rays do not play an important role in life and are reduced. When mating, the end of the gonopodia penetrates the female's genital opening. Sperm are ejected in the form of clots, and sperm enter the ovaries in portions, with a certain time interval. Fertilization of ripened eggs takes place in water.Europeans learned about formosis only at the beginning of the 20th century.
Several portions of sperm settle on the bends of the oviduct and are spent on fertilizing new eggs as they mature. In the absence of a male, females are able to give birth several times, since sperm is well preserved.Formosa lives well in both large and small aquariums.
Heterandria formosa was introduced to Europe in 1912. It is a fairly seasoned fish and tolerates a temporary drop in temperature to 15 ° C; the most favorable temperature regime is 20-24 ° C. During the live birth, the female produces 2-3 fry, and the entire period of “birth” lasts 6 to 10 days. Usually the number of newborn fry does not exceed fifty copies. Repeated “births” occur after a 4-to-5-day break. Adult fish do not pay any attention to fry and do not touch them.The diet of formose consists mainly of plants.
Small and small aquariums are suitable for keeping H.formosa. Most of the feed should be plants. Due to their small size, fish are kept in a special aquarium, but you can plant the Cuban live-bearing fish Quintana atrizona, which is still more heat-loving (23-28 ° C). All other viviparous fish species mentioned in the description love overgrown shady aquariums, in which diffused sunlight sometimes falls. Aquariums are filled with harder water with a slightly alkaline or neutral reaction. Improve the water composition by a small addition of salt in it.