Mortality in groups (immunized fish in good quality water by oral vaccination Containing 0.63 µg KHV Liposome vaccine /fish/day for five days (1.1, 1.2٭) and unvaccinated fish groups in good quality water (1.5, 1.6) and Mortality in groups (immunized fish in bad quality water by oral vaccination Containing 0.63 µg KHV Liposome vaccine/fish/day for five days(1.3, 1.4٭) and unvaccinated fish groups in bad quality water (1.7, 1.8). ٭Significantly difference from control (p≤0.05).