. *Corresponding author Effect of Commercial Probiotic, Bioplus 2B on Water Quality Parameters, Growth Performance and Survival Rate of Poecilia spheno ps in System with no Water Exchange

In aquaculture, water quality plays an important role in health, growth and survival of fish. By increasing demand for environment friendly aquaculture, the use of probiotics in aquaculture is now widely accepted. The effect of commercial probiotics, Bioplus 2B at 0.1 and 0.2 g/l on water quality parameters, growth performance and survival rate of P o e c ili a s p h e n o p s was investigated in system whit no water exchange. The experiment was conducted in Fisheries Group, Faculty of Natural Resources, Behbahan, in the fall of 1385. Nine aquaria with three replicates for each treatment were used. Each tank was stocked with 30 fish (average weight, 1.05 g). Water quality parameters were tested daily. At the end, fish from all the tanks were weighed and counted to calculate fish survival rate and growth performance. Probiotics have no significant impact on the quality of water ( p >0.05), however increased the growth and survival rates of fish ( p <0.05).