Recirculating Aquaculture System (RAS) is a new aquaculture model that uses a series of water treatment units to treat and reuse the wastewater generated in the aquaculture pond. The main principle of RAS is to integrate advanced technologies from various disciplines such as environmental engineering, civil engineering, modern biology, and electronic information, in order to remove harmful pollutants such as residual bait feces, ammonia nitrogen (TAN), and nitrite nitrogen (NO2-- N) from aquaculture water bodies, purify the aquaculture environment, and use physical filtration, biological filtration, CO2 removal, disinfection, oxygenation, temperature regulation, and other treatments to re input the purified water into the aquaculture pool. It can not only solve the problem of low water resource utilization, but also provide a stable, reliable, comfortable and high-quality living environment for aquaculture organisms, and provide favorable conditions for high-density aquaculture. Disadvantages: High initial investment and infrastructure costs. The main reason is the high operating costs of the system, such as electricity consumption, system maintenance, and the need for well-trained staff to monitor and operate the system.