We studied the influence of probiotics containing Bacillus sp (B2) and Bacillus miloliquefaciens (B41) on water quality and white shrimp (Litopenaeus vannamei) performance cultured in tanks. The experiment included two bacterial treatments and one control treatment (no additional bacteria). Each treatment repeated was 3 times. All treatments were done in composite tanks with a stocking density of 50 ind./100L. Bacterial density was 10⁶ CFU/mL. We compared and evaluated the quality of the aquatic environment in the different treatments by measuring temperature, pH, DO, COD, TSS, TAN and total alkalinity. Samples were analyzed before the bacteria were added and then periodically collected 1 time/5 days until the end of the experiment (60 days). Sample collection and analysis was completed according to standard methods (APHA, 2005), and were undertaken in the water quality laboratory of the College of Aquaculture and Fisheries, Can Tho University. After the end of experiment, we found that the temperature, pH, total alkalinity remained stable and within acceptable permitted aquaculture ranges. However, factors such as DO, COD, TSS, and TAN varied between treatments and tended to increase towards the end of the experiment. They were still suitable for shrimp farming. The density of Vibrio in additional bacterial treatments were lower than in  the control. The survival rate of shrimp in treatments B2 (70.0 ± 5.3%) and B41 treatments (86.7 ± 3.1%) were significantly  higher (p< 0.05) than compared with those in the controls treatments (65.3 ± 3.1%) .