Because of the importance of rotifers as an adequate live food in larviculture, this study was conducted to evaluate probiotic potency of four microorganisms, Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei and Bacillus natto on suppression of Vibrio species and increasing population growth, enzymes activity and nutrients retention in the rotifer, Brachionus plicatilis. Four experimental and a control treatment, each with four replicates, with the concentration of 10(8) CFU/mL(-)(1) for each strain were applied. The results demonstrated that L. sakei and B. natto successfully suppressed Vibrio in experimental treatments and increased population growth and nutrients retention. The longevity of B. natto was recorded as the best in long-term inoculation than other treatments and the control in a way that after 8 days of rotifers starvation, the count of B. natto increased. The findings showed that the two bacteria, B. natto and L. sakei, appear to be a promising probiotic for rotifers in suppressing Vibrio and also in increasing population growth, nutrients retention, enzymes activity and long-term inoculation in rotifers