The present study was to evaluate the effects of dietary supplementation of lactobacillus acidophilus on growth performance and feed efficiency, digestive enzymes activity and some hematological parameters of Golden severum. In this study, 120 fish (Heros severus) with an average weight of 18.72±0.3 g distributed within experimental tanks, four treatments with 3 replications were arranged. Fish were fed 4 different levels of Lactobacillus acidophilus (0, 1.5×108, 3×108 and 6×108) for 60 days. At the end of the experiment, growth parameters, feed efficiency, digestive enzymes activity and hematological parameters were investigated. Results showed that lactobacillus significantly (p<0.05) improved growth performances and feed conversion ratio of fish. Dietary supplementation of probiotic Lactobacillus acidophilus resulted in significantly higher lipase, amylase, alkaline protease and alkaline phosphatase in golden severum (p<0.05). Also, hematological parameters were affected with probiotic supplementation the extent that those fish fed a diet containing probiotic significantly showed higher hematocrit, hemoglobin and white blood cells. According to the results, the appropriate supplementation level of L. acidophilus for golden severum is determined in this study and can be considered in culturing of this fish species.