It was studied the fish species of the upper part of Kaniv reservoir (Kyiv water area) and the mouth area of the Desna River. The found and preceding data of ichthyological research were compared. The changes in the fish population were analyzed. Two new invasive alien fish species were discovered in the Kaniv reservoir and Desna River: Amur sleeper (Perccotus glenii) and Stone moroco (Pseudorasdora parva). Generally the ichthyofauna composition of these water bodies was supplemented with seven unmarketable and dirt species.