Mixed culture of fish and ducks is one of the best models for comprehensive management of fish and livestock and poultry. Its advantages are: first, raising ducks in fish ponds can increase oxygen in fish ponds. Second, it is conducive to improving the nutritional environment of fish ponds. Third, ducks can provide organic bait for fish. Fourth, it is beneficial to prevent and control parasitic diseases of fish and ducks. By adopting this technology, fish 1 00-250kg can be produced per1/5 hectare (1mu) of water surface, and the yield can be increased by 15%-35%. At this stage, there are three main ways to polyculture fish and ducks: one is grazing. That is to say, putting ducks scattered on the surface of ponds or lakes is beneficial to raising fish in large waters and saving some duck feed, but it has little effect on fish production. The second is to raise ducks outside the pond. That is to say, build a duck shed near the fish pond, set up a cement activity field and an activity pool, and wash the duck manure and residue on the activity field into the fish pond every day. This way is convenient for centralized management of ducks, but it can't give full play to the advantages of mutual benefit between fish and ducks. The third is direct polyculture. A semi-circular duck shed is separated by a net at the inner side of the dam or the corner of the fish pond, which is used as a playground and sports pool for ducks to be directly stocked in the fish pond. The duck shed faces the fish pond and has a spacious shed door, which is convenient for putting ducks into the water and cleaning up feces. This method can give full play to the ecological effect of mutual benefit between fish and ducks, and it is a common mixed culture method of fish and ducks in China. Generally, 50-60 ducks per115 hectare are suitable for duck breeding in mixed fish ponds. If too many ducks are released, duck manure will be deposited, and the water color will be too strong, which will lead to hypoxia in fish ponds and even the death of fish species. If too few ducks are released, the water will be pale, resulting in less plankton and more material consumption, which will also affect the economic benefits of fish ponds. At the same time, the fish pond should be stocked with upper, middle and lower layers of fish, and the bait should be swallowed in layers to avoid the waste of rabbits. When selecting water surface, adult fish ponds or 2-year-old fish ponds with an area of more than115 hectares and a water depth of more than 1.5 meters are generally selected. Fish with a body length of less than 4 cm are small and slow to swim, and are easily swallowed by ducks. Therefore, it is generally not suitable to put ducks in fish ponds of 1 year old. In a shallow pond, ducks will stir mud, make the water turbid, and fish will surface and be swallowed, which is not suitable for raising ducks. Choose suitable rivers, small lakes and reservoirs. Slope protection should be built for sand ridges on newly dug fish ponds, pond ridges with loose soil and duck pens. Daily management In order to facilitate centralized management, a small number of fish ponds can be enclosed with nets, screens and other materials as duck activity pools. It is best to raise 2-4 ducks per square meter of water surface, and the net is 40-50 cm above and below the water surface, so that fish can freely enter and leave for food, even if small fish are nested, the loss can be reduced. Every morning and evening, the ducks are fed in the activity field of the pool ridge, and after the ducks enter the shed at night, the duck manure in the field is cleaned up in the pool. Drive the ducks out of the shed in the morning, pick them up and clean up the duck manure in the shed into the pool. In summer, ducks excrete a lot of feces, and the water quality is too fat. It is necessary to replenish fresh water in time and reduce the amount of fertilization. When ducks are old and defecate for a long time, duck farms are semi-arid and semi-arid, so that some ducks produce feces on dry land. In addition, change water and increase oxygen in summer.