The research was conducted to identify the fish availability and fish marketing system in different markets of Ashuganj upazila under Brahmanbaria district. Data were collected from fish retailers, wholesalers and consumers of three different markets namely Ashuganj Bazar, Ferryghat Bazar and Khariyala Bazar through individual interviews and focus group discussion. The maximum 19 species were found in Ashuganj Bazar while 16 species were found in Ferryghat Bazar and 14 species were found in Khariyala Bazar. The species composition included 36% Catfishes, 15.33% SIS, 11.33% Ilish, 6.66% Thai pangas, 6% Prawn and Shrimp, 6% Marine fish, 6% Carps, 5% Tilapia and 2.33% Thai koi. The daily average gross profit of fish retailers in Ashuganj Bazar, Ferryghat Bazar and Khariyala Bazar were estimated as Tk. 550/day, Tk. 500/day and Tk. 480/day respectively. The results showed that 62% of the retailers have improved their socio-economic condition through fish selling. A number of constraints such as lack of storage facilities, poor supply of ice, exploitation by middleman, lack of money and lack of infrastructure were reported by the retailers.