The first fish to visit space (aboard the Salyut-5 orbital station) is the guppy, one of the most unpretentious aquarium fish. This cute colored little fish gives birth to fry with ease, even in a glass of water. The area of the initial distribution of guppies is considered the islands of Trinidad, Barbados, Martinique and Saint Thomas. Guppies live in both fresh and brackish waters of Venezuela, Guyana, Costa Rica, north and south of Brazil. They also took root in Mexico, USA, Italy, Madagascar, India and West Africa. Such a wide distribution of the guppy is due to the fact that it is an enemy of mosquitoes and mosquitoes, diptera bloodsuckers and carriers of malaria. In the second half of the 19th century, Europeans noticed that on one of the West Indies islands, where water bodies were literally teeming with guppies, the local population almost did not suffer from malaria. And at the same time, on the neighboring islands, where this fish was not, the disease was raging. It was then that the guppy became widely known: they wrote about her in scientific books and magazines, newspapers called her the savior of mankind. And doctors and biologists settled the fish in new reservoirs, transported them to different countries. The incidence of malaria did indeed decrease: the guppies ate eggs, larvae and pupae of mosquitoes and mosquitoes. This fish, like the Drosophila fly, faithfully serves genetics as well: experiments on crossing different variations of guppies helped to study the laws of heredity. Guppies also test the degree of wastewater treatment, the effects of household chemicals and heavy metals.