摘要:Alternative prevention should be developed to control disease outbreaks in Tilapia culture caused by co-infections of Aeromonas hydrophila and Streptococcus agalactiae. Applications of vaccines with low cost and simple methods are highly recommended. This study was conducted to find out the safety and the efficacy of immersion vaccine in Tilapia used bivalent vaccines with formalin inactivated of S. agalactiae and A. hydrophila. Tilapia (Oreochromis niloticus) were divided into two groups, vaccinated and not vaccinated, with single and double doses immersion. The results showed that single and double doses of immersion vaccine were safe for fish (SR 100%) and effectively increased the antibody titer values compared to non-vaccinated fish. The immersion vaccine method can be recommended as an alternative to controlled fish diseases, especially for both Motile Aeromonads Septicaemia and Streptococcosis caused by A. hydrophila and S. agalactiae infections, respectively.