Maintaining good water quality can stimulate the appetite of tilapia, reduce the feed coefficient, and improve the growth rate of fish. In the early stage of breeding, in order to save costs, the use of fertilizer water culture. But in the mid-term, it is necessary to add new water in time to adjust the water quality. Gradually, the water quality of aquaculture complies with the relevant provisions of my country (GB11607-1989) "Water Quality Standards for Fisheries" and "Water Quality Standards for Pollution-Free Foods and Freshwater Culture (NY5051-2001)". Timely water change, new water filling, and mechanical oxygenation are important means of regulating water quality. Therefore, new water should be added to the pond every 3 to 4 days, 20 to 30 cm each time. When the water quality deteriorates, you should change the water as soon as possible, first drain 1/3 to 1/2 of the pond water, and then add new water until the water quality becomes better. The pH value of the pool water can always be kept between 7.5 and 8.5, and the transparency can be kept at 25 to 30 cm by sprinkling the whole pool with quicklime 10-15 mg/L every once in a while. When adding new water, pay attention to filtering the new water, filter out the wild fish, and strictly prevent other tilapia from entering the pond to breed and mix. Affect the growth and yield of tilapia.