From Latin Fauna - goddess of forests and fields, patroness of animal herds.

Fauna is a historically developed set of species or other systematic groups (genera, families, etc.) of organisms inhabiting a given water body.

The concept of fauna has both a systematic and a geographical content, so the principle of limitation should be geographical (fauna of the island of Cuba, fauna of Zimbabwe, fauna of Eurasia, etc.) and systematic (fauna of birds (ornithofauna), fauna of insects (entomofauna), fauna of fishes (ichthyofauna), etc.). The latter is due to the fact that, in practice, it is impossible to obtain a complete list of the species of a given territory, both because of their great diversity and because of the lack of systematic specialists.

One of the main indicators of fauna is the proportion of endemics - it shows the degree of isolation and age of the fauna.