Animals that are found in the life of man, directly or indirectly affect health and existence, depending on the number, way of life, proximity to humans and some of their biological manifestations. Protozoa to their characteristics bacterivore, involved in limiting and then restore normal number of bacteria in a medium. Between protozoa and parasitic worms are some species that can infect humans and animals, causing disease. Frequency of parasites is sometimes extremely high, tending to children in rural and urban areas, even at 100%. Parasitic environmental pollution is one of the current serious problems. In order to provide the population of our country with high-quality fish products, it is necessary in industrial aquaculture to switch to technologies of closed water supply installations. A consequence of human actions on the animal world is the consumption or total destruction to extermination and extinction of species. Biodiversity conservation work but to go missing crisis must do more, and faster.