Fish farming practices currently make effective use of probiotic Bacillus species, specifically Bacillus subtilis and B. licheniformis. The current study assessed the water quality, growth performance, body composition, hemato-biochemical activities, immune regulatory genes, and resistance to Aspergillus flavus in order to determine the effectiveness of the water additive probiotic Bacillus species mixture (SANOLIFE®PRO-W) on Nile tilapia aquaculture. Fish were kept in four groups (control, 0.01, 0.02, 0.03) gm. /m3for 56 days using Bacillus species in-water treatment. The results showed that the fish treated with SANOLIFE® performed significantly better (P