The present study tried to investigate the effects of probiotic, Pediococcus acidilactici in concentrations of 1× 10⁹, 2× 10⁹ and 3×10⁹cfu kg^-1 diet on growth and survival rate of oriental bream fry (Abramis brama orientalis, Berg 1949) in comparison to control diet (devoid of probiotic) for 60 days. In so doing, 180 specimens of oriental bream with initial weight of 2.69± 0.22 g were divided randomly into12 fiberglass tanks (capacity 110 l).They were fed at 3-5 percent body weight daily. A the end of the trial, growth and survival rates were measured.  The best growth performance was viewed in treatments rather than the control because of the improvement of gut microflora balance, which performed by probiotic P. acidilactici, following by the enzyme secretion for increasing nutrient digestibility and fish appetite. The best bodyweight gain, specific and daily growth rates, and  the lowest feed conversion ratio was observed in treatment, feeding with diet containing 2× 10⁹cfu kg^-1 diet (P<0.05). The results of the current study revealed that it is the role of probiotic, P. acidilactici to the diet of oriental breamfry and A. brama orientalis, which resulted in growth performance increase and feed efficiency ratio improvement.