The population structure of Aphanius anatoliae in Lake Egirdir-Isparta-Turkey was studied, using 522 fish monthly in 2008. This study were observed in the number of individuals of each sex, age, weight and size compositions. In addition, the total length-weight relationship was calculated as well as the Von Bertalanffy growth equation. A study of the food uptake throughout the year has been carried by examination of the content of the digestive track. Males made up 51.92%, and females 48.08% of the population. The length-weight relationship and Von Bertalanffy growth equation were estimated as W= 0.0232 e (0.098L), r=0.8262, L-t = 54.51 ( 1 - e (-0.279) ((t+1.345))), respectively. Bacillariophyta, Gammarus pulex and aquatic insecta are the major food items for Aphanius anatoliae.