Fuxian Lake is known for its unique fauna, including many endemic species. However, its relative isolation makes it vulnerable to biological invasions and pollution.
In total, there are 25 native fish species in the lake, including 12 endemics.
Many of these species are in precarious situations because they have been negatively impacted by introduction of exotic species of fish, habitat degradation, water pollution, and overfishing. The table below lists endemic species, all cyprinids, that have declined strongly; some of them may already be extinct.