The current work was conducted to evaluate the impacts of Bioflocs (BFT) based system and probiotic additions in nursery phase of juvenile common carps (Cyprinus carpio). Effects of a probiotic PondToss™ containing a mixture of different Bacillus subtilis, B. amyloliquefaciens, B. pumilus and B. Bacillus licheniformis), 5.9×10⁷ CFU/ gram was tested for growth measurements and health status. In a completely randomized design, four experimental treatments were replicated and subjected to be studied as T1: fish held in clear water nursery tanks (CWNS), received no probiotic PondToss™ (the control group). The T2, CWNS tanks supplemented with probiotic PondToss^TM at 2.0 billion CFU/ gram at a dose of 1 g/ kg of diet. T3: fish held in BFT tanks without supplementing probiotics whereas the T4 BFT Tanks supplemented with probiotic PondToss^TM at 2.0 billion CFU/ gram at a dose of 1 g/ kg. Fish were fed the experimental diet for 12 weeks and the results at the end of this work demonstrated that, the highest (worst) levels of nitrogenous compounds were recorded in T1 however, the corresponding improved values were in favor of T4 (BFNS+ Probiotic PondToss™). The fish group in T4 biofloc nursery system (BFNS) supplemented with probiotic PondToss™) showed a significant (P<0.05) increase in final live body weiht gain, ADG and specific growth rate (SGR, %/day) compared to other groups. survival rates were improved in BFNS (98.33 %) and BFNS-probiotic enriched group (99.58%) compared to the control 92.5%. the biochemical parameters were significantly improved in biofloc based nursery system (BFNS) and were in favor where probiotic was added. A continuous intake of mixture probiotic Bacillus subtilis, B. amyloliquefaciens, B. pumilus and B. licheniformis, 5.9×10⁷ CFU/ gram at a dose of 1 g/ kg of feed in Biofloc based nursery of carps is recommended due to the improved performance, survival and helth status.