Recently, the antibacterial drug resistance and conventional dosage forms with their side effects increases  in aquaculture were induced more medical plants applications. Therefore, in this study minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) in Aeromonas hydrophila were evaluated by succession dilutions of Walnut extracts.  In addition, zone of  bacterial growth inhibition were analyzed using by agar diffusion test. Results showed that 37.5mg/ml of ethanolic and 75 mg/ml of water extraction doses were functioned as a MBC. Moreover, we saw 18.75 mg/ml of etanolic and 37.5mg/ml of water extraction doses were MIC’s. In addition, diameters of growth inhibition zones were confirmed results. Overall, we suggest ethanolic and water extracts of Walnut as an antibacterial material can examine in farm experiments