Milkfish is an Indonesia fishery commodity that has high economic value. However, promising potential can face serious problems in the milkfish larvae caused by bacteria. The solution that has been done is by providing sufficient feeding. However, this method is less effective because it only has significant effect on fish growth, but does not inhibit the growth of microbes in post-larvae of fish. Therefore, the authors innovate in the form of the addition of ozone and silver nanoparticles to the larval maintenance media. The purpose of this study is to reduce the mortality rate of milkfish larvae caused by bacteria. The research methods used in this study are observation, literature studies, and laboratory studies. This research was carried out by keeping the milkfish larvae for 20 days. This study compared the treatment of P0 (control), P1 (400 mg ozone), P2 (Silver Nanoparticles 0.5 ppm), and P3 (400 mg ozone and 0.5 ppm Silver Nanoparticles), so that it can be known the better of the maintenance media of milkfish larvae. The data are analyzed by qualitative quantitative. Based on the results of the study, the best total bacterial test results are P1 as much as 3,200 CFU/ml and the total test results of Vibrio sp. bacteria. The best result is P2 as much as 36.67 CFU/ml, so it can be concluded that silver nanoparticles can inhibit the growth of Vibrio sp. and the increase in bacteria is treated to be caused by unusable feed. The best hatching rate observation in P3 is 90.61%. The best survival rate observation in P3 is 91.03%. The highest absolute growth tally in P3 reached 15.61 mm. Based on these results, it can be concluded that the best treatment is P3 because it can inhibit the growth of Vibrio sp. and it has an effect on the growth rate of larvae. The results of water quality data during the study achieved optimum and appropriate with the milkfish seeding standard. In this study, temperatures is in the range of 28-31°C, pH is in the range of 6.49-7.84 and salinity is in the range of 30-31 ppt.