AbstractMany factors , such as pollution , species int roduction and reclamation around the Lake , have made the indigenous fishes in Dianchi Lake tend to decline or bcome endangered. The results from a survey conducted in 2000 showed that there are only 11 indigenous fishes remaining , and seven of them disappeared for many years in Dianchi Lake but still live in the upper reach of the rivers that flow into Dianchi Lake. By field survey of the indigenous fishes and their habitats , integrated with literature records , the historical change of the indigenous fishes , the spatial change pattern of their habitat sand the factors cont ributing to the fast decline of endemic fish diversity have been analyzed. Measures and approaches have been proposed here to protect these indigenous fishes.