摘要：Gajah Mungkur reservoir with an area of 8,800 ha is the result of the damming of Bengawan Solo River and several tributaries. The Inlet and outlet waters of Gajah Mungkur reservoir have different biotic and abiotic factors which are considered affecting the diversity of species of fish. Thus, this research was conducted in order to determine the diversity of fish species of fish on the inlet and outlet area of Gajah Mungkur reservoir Wonogiri. Sampling was conducted in January-February 2013. There are 3 inlet locations and 1 outlet location to catch the fish with sampling method that was making the plot of (50 x 20 x 1.5) m3, time arrest for 20 hours. Fish species was identified by using Kottelat (1993). Fish species diversity calculated by Shannon Wiener diversity index. Relative abundance is used to look at the density of fish at each location. The relationship between the abiotic factors and species diversity of the fish's body morphological characters were analyzed with correlation test. The results showed that the diversity of fish species in Gajah Mungkur reservoir in the outlet is higher (1.87) than the inlet locations I, II, III (1.02, 0.71 and 1.23). Abiotic factors have a significant influence on the distribution and spread of fish
