The impact of different concentrations (5, 10, 15 and 20%) of the seaweed, Ulva rigida on the growth performances and proximate composition on Poecilia latipinna was examined. Better growth performances in terms of weight gain, FCR, SGR, ADG and RWG were recorded in E2 (10%) Ulva rigida group. Beyond that concentration, the growth started declining. As far as the body composition was considered, E2 showed the highest and significantly different (p0.05) in the carbohydrate and lipid levels among the groups. Key words: Ulva rigida, growth performances, proximate composition, Poecilia latipinna.