The aim of this study is to distinguish three different types of fish which are anchovy, horse mackerel and whiting by an electronic nose. Generally, the electronic noses are composed of three units. These are sensor unit which has 8 metal oxide sensors in this study, an electronic unit and a pattern recognition unit. In the pattern recognition unit, signal preprocessing, feature extraction and classification stages are performed. For distinguishing different fish species, different feature extraction methods and classification methods are compared with each other. Then the best combination of feature extraction and classification method is selected and applied to the fish database.