A study was undertaken on the effect of probiotic bacteria, belonging to genera Bacillus and Streptococcus, on survival, growth and production of wild-collected red snapper, Lutjanus argentimaculatus in marine cages for a period of 90 days. Wild-collected juvenile fish with an initial biomass of 0.79 kg/m3 were stocked in marine cages at Karwar, India. All the fish (control and probiotic treated) were fed with pellet feed at 10% fish biomass. The feed was supplemented with multi-strain probiotic combination (T1) and with single-strain probiotics (T2 and T3). Growth, survival of fish, and microbiological parameters were monitored at fortnightly intervals. After 90 days of culture, the final mean weight (g), Absolute Growth Rate (AGR g/day), and Specific Growth Rate (SGR%/day) of fish were recorded as 250 ± 0.5 g; 2.23 ± 0.012 g/day; 0.79 ± 0.052%/day, respectively, in T1. A significant difference (P < 0.05) among the different treatments was recorded, and T1 showed a higher growth rate. The highest survival rate was recorded in T1 and T2 and varied significantly among the treatments (P < 0.05). Microbiological analysis of fish gut revealed the presence of Bacillus species as the dominant group in T1, followed by T2. A significant variation (P < 0.05) was recorded in total bacterial and Bacillus loads among all the treatments. The results of the study indicated that the application of 0.1% of multi-strain probiotics as a supplementary diet is economically viable and also enhances the survival, growth, and production of cage-cultured L. argentimaculatus.A study was undertaken on the effect of probiotic bacteria, belonging to genera Bacillus and Streptococcus, on survival, growth and production of wild-collected red snapper, Lutjanus argentimaculatus in marine cages for a period of 90 days. Wild-collected juvenile fish with an initial biomass of 0.79 kg/m3 were stocked in marine cages at Karwar, India. All the fish (control and probiotic treated) were fed with pellet feed at 10% fish biomass. The feed was supplemented with multi-strain probiotic combination (T1) and with single-strain probiotics (T2 and T3). Growth, survival of fish, and microbiological parameters were monitored at fortnightly intervals. After 90 days of culture, the final mean weight (g), Absolute Growth Rate (AGR g/day), and Specific Growth Rate (SGR%/day) of fish were recorded as 250 ± 0.5 g; 2.23 ± 0.012 g/day; 0.79 ± 0.052%/day, respectively, in T1. A significant difference (P < 0.05) among the different treatments was recorded, and T1 showed a higher growth rate. The highest survival rate was recorded in T1 and T2 and varied significantly among the treatments (P < 0.05). Microbiological analysis of fish gut revealed the presence of Bacillus species as the dominant group in T1, followed by T2. A significant variation (P < 0.05) was recorded in total bacterial and Bacillus loads among all the treatments. The results of the study indicated that the application of 0.1% of multi-strain probiotics as a supplementary diet is economically viable and also enhances the survival, growth, and production of cage-cultured L. argentimaculatus.