Vaccine is alternative to prevention bacteria of Aeromonas hydrophila. The objective of this research was to findout how long the best immersion time of jambal siam (P. hypophthalmus) given vaccinated A. hydrophila. The fish used during this research were 8-10 cm as many 250 tails. This research was conducted in April – Juni 2018. The purpose of this research was to given understand the hemat…