Water quality control and management are very important links in shrimp culture. The quality of water quality management directly determines the success or failure of shrimp culture. First, the influence of water quality factors on aquaculture. The water quality index of shrimp culture water is usually expressed by dissolved oxygen, pH value, ammonia nitrogen, hydrogen sulfide, salinity, water color taste and transparency. Dissolved oxygen is not only an essential substance to ensure the normal physiological function and healthy growth of prawns, but also an essential substance to improve the water quality and sediment. It is best to keep dissolved oxygen above 5 mg/L in the prawn culture process, and generally it should not be lower than 3.5 mg/L.. Ammonia nitrogen and hydrogen sulfide are harmful substances in shrimp culture, and their concentrations and contents in water should be controlled below 0.5 mg/L and 0. 1 mg/L respectively. PH value is a comprehensive index to reflect the water quality, which is closely related to the content of plankton and dissolved oxygen in water, and also affects the content of ammonia nitrogen and hydrogen sulfide. It is appropriate to control the pH value at 7.6 -8.8 in shrimp culture. Transparency is an indirect physical index reflecting the amount of phytoplankton and organic detritus in water. Generally, the transparency should be lower in the early stage and higher in the later stage, which should be controlled within 30-60 cm. Taste is an indicator of whether there are putrid organic substances in the bottom water of the pond, especially the bottom mud. If the water body is black and has a foul smell, it means that there are too many putrid organic substances underwater, which is easy to cause diseases. Second, the judgment and identification of water quality changes In the process of shrimp culture, water color and its changes are important indicators to judge the quality of water. 1, if the water mainly contains diatoms, Nitzschia crescent, Chlorella, Chaetoceros, Phaeodactylum tricornutum, etc., the water color is reddish brown. Red-brown is the best water color for shrimp culture, and these algae are high-quality bait for shrimp. 2. If the water body mainly contains green algae, the water body is light green and emerald green. Green algae can absorb a lot of nitrogen and purify water quality, which is also the water color that farmers expect. 3. If the water body mainly contains golden algae, the water body is light yellow and golden yellow, which is also a better water color for shrimp culture. However, the mud injected into the shrimp pond after the rainstorm will also make the water yellow, so it is necessary to distinguish between different situations to judge. 4. If the water body is dark green, it contains more cyanobacteria; if the water body is dark brown, it contains more flagellates, green algae and brown algae, which are all signs of excessive organic matter and are bad water colors. 5. If rotifers and copepods are dominant in the water, the water will be white and turbid, which will reduce the survival rate of prawns. 6. If there is too little plankton in the water, the water is too thin and the water is clear. Clear water shows that phytoplankton died in large numbers. If there are more ciliates and noctiluca, and the water is red, it is easy to cause hypoxia and illness. By observing the activity of prawns, the dissolved oxygen in water can be judged. The omen of water hypoxia is: the transparency of water is less than 30 cm or more than 80 cm; Shrimp roams feebly on the water during the day; The water color is turbid white; The black area at the bottom of the pond is large and smelly; There are many mosquitoes around the shrimp pond after sunset. In addition, in the high temperature period in summer, the weather is sultry and windless, or it is easy to lack oxygen on continuous rainy days. At this time, it is necessary to start the aerator, add water, change water or use the aerator in time.