To identify the behavior of fish consumer in Iran's largest fish market in order to improve sales and obtain customer satisfaction. After designing and completing the questionnaire, descriptive statistics and Friedman test, chi-square and stepwise regression were used for data analysis. Consumers were very much in agreement with the direct sale of Fish by producer in the market, government subsidies to buy fish, and the aquatic properties on the market. Their highest priority is to buy trout and then southern fish, shrimp, Caspian Sea fish and warm-water fish. More than half of consumers were introduced to the market for the first time through advertising and introducing their friends and acquaintances, and 46% were familiar with the market because of their home proximity. The most important marketing mix was advertising, and the most important reason for buying fish from this market was the freshness and diversity of the fish. Research shows that men buy more fish than women cross-country people, women born in coastal areas and high-income buyers. Given the tendency of consumer to be familiar with the market and the importance of advertising, paying attention to this and targeting male buyers will be very effective in market prosperity. Considering the numerous research results, including inserting aquatic properties and installing electronic signage on and off the aquarium in the market and helping improve household income is another way to improve customer satisfaction.