Oxyphilous species are fish that require significant oxygenation of water, not less than 7 mg/l, to live. These are trout, grayling, taimen, lenok, nelma, Siberian char, podkamenchiks and others. Oxyphilous fish are more sensitive to changes in the water level in the reservoir compared to fish that can more easily tolerate some oxygen deficiency.

Oxyphilicity - inhabitation of these species in oxygen-rich water bodies. Oxyphilicity allows to spend minimal resources on the development of gill surfaces, their protection and blood supply. Therefore, in biotopes always rich in oxygen, oxyphilous organisms usually win the competition with eurybionts and dominate.