We studied 235 specimens of fish and found that 8 species had blood parasites. These species are: Pike, Vobla, Murzo, Bream, Prussian carp (Goldfish), Carp, Catfish, Zander. Other spices of fish such as Trout, Chub, hybrid of Vobla and Bream, Kura khramulya, Kura barbel, Kura shemaya and Grass carp were free from the blood parasites.

To infect aquatic vertebrates with blood parasites in water reservoirs there should be first of all conditions for living and development of leeches – carriers of blood parasites which prefer well-warmed stagnant or slow-flowing water reservoirs with abundant vegetation. This article presents the hydro-biological characteristics of the studied water reservoirs.