This study was conducted to test the effect of taurine on growth performance, muscle composition, digestive enzyme activities, amino acid profiles and blood biochemistry of beluga (209.1 ± 23 g) in both fresh water (FW) and brackish water (BW: 15 ppt). Twelve experimental treatments with six taurine levels, for FW (Tau2.1, Tau4.3, Tau7.1, Tau12.3, Tau16.7 and Tau21.8) and BW (BwTau2.1, BwTau4.3, BwTau7.1, BwTau12.3, BwTau16.7 and BwTau21.8) were designed to feed and farm fish for 8 weeks. Generally, fish farmed in BW had better performance regarding growth. Regarding amino acid profile, fish‐fed moderate dosages of taurine (7.1 and 12.3 g/kg) had higher and lower taurine and serine in muscle, respectively. Beluga‐fed diets with 12.3‐ and 16.7‐g/kg taurine in FW and BW had the highest growth rate in line with the highest amylase and protease activities, alanine transaminase and aspartate transaminase; and lowest lactate dehydrogenase, triglyceride and cholesterol. The lipid‐lowering effect of taurine was observed. In conclusion, supplementation of beluga diets with 12.3‐ to 16.7‐g/kg taurine for farming in both FW and BW is required.