The present study investigated the effect of Mao (Antidesma sp.) juice concentration on the growth rate and infection resistance to Streptococcus spp. in the Nile tilapia fish with an initial weight of 12.65 ± 0.14 g. The experiment was divided into the control (0), 60, 40 and 20% Mao juice mixed feed powder, respectively. At the end of the 60-day experimental period, the average daily growth values were 0.49 ± 1.22,0.29 ± 0.71,0.39 ± 0.78 and 0.43 ± 0.48 gD^-1, respectively, the specific growth rates were 5.62 ± 0.66, 4.75 ± 0.49, 5.25 ± 0.55 and 5.41 ± 0.39 %D^-1, respectively, feed conversion ratios were 1.83 ± 2.11, 2.78 ± 0.88, 2.13 ± 0.67 and 1.68 ± 0.53, respectively, and the survival rates were 76.19 ± 0.32, 84.52 ± 0.47, 82.14 ± 0.73 and 94.05 ± 0.47%, respectively. There were significant (P <0.05) differences. The results from injection of Streptococcus agalactiae and Streptococcus ineae in Nile tilapia fed at the 20% Mao juice level had the lowest cumulative mortality at 43.33 ± 5.77% and 70.00 ± 10.00%, respectively. The results showed that the 20% Mao juice level had a positive effect on the growth rate and resistance to S. agalactiae