This study evaluates the effects of supplementing whiteleg shrimp (Penaeus vannamei) feed with Streptomyces strains (TM₁, TM₂, TM₇, TM₂₁, TM₂₂), Bacillus strains (AQ₁, BIO₂, BAL₃), and their combinations at different densities (10⁶, 10⁷, and 10⁸ CFU/g) on growth performance, immune response, water quality, and Vibrio control. Two experiments were conducted over 36 days: the first tested individual Bacillus and Streptomyces consortia at varying doses, and the second assessed combined treatments. Survival was monitored after shrimp were fed probiotics and subsequently challenged with Vibrio parahaemolyticus. Results showed significant improvements in final body weight (FBW), daily weight gain (DWG), feed conversion ratio (FCR), survival rate (SR), and total hemocyte count (THC) in all probiotic treatments, with greater benefits at higher probiotic doses. Combined probiotic treatments consistently produced greater numerical enhancements in growth performance than single-strain applications, indicating synergistic effects between Streptomyces and Bacillus consortia. Water quality responses differed between probiotic types, with Streptomyces treatments providing rapid early reductions in total ammonia nitrogen (TAN) and nitrite, whereas Bacillus-supplemented treatments achieved delayed but more stable and higher removal efficiencies toward the end of the experiment. The combination treatment B8S8 (Bacillus and Streptomyces at 10⁸ CFU/g each) yielded the greatest growth enhancement (approximately 143% FBW and 149% DWG increase relative to the control) and effectively reduced Vibrio counts, achieving 2.9 and 3.1 log reductions in water (B6S8 and B8S8, respectively) and 3.5 and 3.6 log reductions in the shrimp gastrointestinal tract. In combined treatments, TAN and nitrite removal efficiencies exceeded 95% by Day 36, with no significant differences among probiotic combinations. This probiotic supplementation strategy enhances shrimp health and growth in recirculating aquaculture systems at 100 shrimp/100 L, suggesting that combined Streptomyces and Bacillus consortia are a promising approach for improving P. vannamei aquaculture productivity.