Bacillus belongs to the genus Bacillus, which is a gram-positive aerobic bacteria. The strain is nontoxic and can secrete protease and other enzymes and antibiotics. Nitrate and nitrite can be directly used to purify water. In addition, the secreted enzymes and antibiotics can be used to inhibit the growth of other bacteria, thus reducing or even eliminating the pathogens of aquaculture animals, reducing the occurrence of diseases and improving the efficiency of aquaculture. It can improve the intestinal flora of aquatic animals, enhance the digestion and absorption function of animals, promote the utilization of calcium, phosphorus and iron by animals, promote the absorption of vitamin D, enhance the body's disease resistance and reduce the feed coefficient.