Nizhnaya Tunguska river is the second largest right tributary of Enisey river. Biodiversity and biology of fish of the given water body are still insufficiently examined at the present time. There are more detailed information about species composition of lower flow of the river. It contains brief data on habitation of 30 species of fish and cyclostomata. Composition of species of the middle flow wasn’t cited previously. Contemporary information about speies diversity of part of middle flow of Nizhnaya Tunguska river, which practically wasn’t examined yet, is cited in this article. Brief characteristic of main biological attributes: age structure, linearly-weight growth, time of pubescence, fertility and diet. In the course of the survey, habitation of 14 species from 7 families of fish was determined in the middle flow of Nizhnaya Tunguska river. Hucho taimen was found in the given part of river for the first time.