This study investigated the antibacterial effect of flavomycin and synbiotic against Pseudomonas aeruginosa (p. aeruginosa) beside the weight gain and hemato-biochemical changes in common carp. Apparently healthy 150 common carp weighing 110 ± 10 g were divided into six equal groups. The 1st group received basal diet without any additives (control group). The 2nd group received basal diet with 8 mg/kg diet flavomycin for 30 days. The 3rd group received basal diet with 3 mg/kg diet synbiotic for 30 days. Fish in 4th, 5th and 6th groups were experimentally infected with P. aeruginosa. The 4th group was left untreated. The5th and 6th groups were treated with 8 mg/kg diet flavomycin or 3 mg/kg diet symbiotic, respectively for 5 days. Swabs were collected to reisolate p. aeruginosa. Blood samples were collected for hemato-biochemical analysis. Healthy fish received flavomycin or synbiotic revealed significant increase in body weight gain, RBCs, Hb, PCV with non-significant increase in total protein, albumin, globulin, A/G ratio, AST, ALT, urea, creatinine. Infected fish with P. aeruginosa showed tail and fin rot, hemorrhagic ulcerative skin, superficial ulcers beside mortality rate up to 32% with significant decrease in body weight, RBCs, HB, PCV %, total protein, albumin, globulin and significant elevation in AST, ALT, ALP, urea and creatinine. Infected fish treated with flavomycin or synbiotic improved the clinical signs, reduced mortality rate to 8% and 12%, respectively, and decreased rate of infection. In conclusion, flavomycin or synbiotic has effective antibacterial effect against P. aeruginosa.