Moss is actually a filamentous algae, which is common in fish ponds and adult fish ponds. When it breeds in a large number in the pond, it will make the water in the pond dilute sharply and affect the growth of fish. Generally, when the water temperature rises in spring and autumn, it begins to germinate and grow gradually. Once the fry or fry enter the moss, it is difficult to swim out, leading to death. 1, preventive measures ① Cleaning the pond with quicklime can remove moss. ② Filter the water source to avoid bringing moss into the pool. 2, prevention and control methods ① Sprinkle 50 kilograms of plant ash on the moss in the pond without fish, which can make the moss die without sunshine; The pond where fish have been put can be sprayed with 0.7× 10-6 copper sulfate according to the water depth per mu 1 m, which can kill moss. (2) For water with a depth of1meter, use 50 kilograms of gypsum powder per mu, and spray it all over the pool for three times, with an interval of 3-4 days. If the amount of moss is large, the dosage can be increased to 65 kilograms of gypsum powder per mu, and applied after the rain in the afternoon. If conditions permit, fresh water of 10 ~ 20 cm can be injected after smearing, and the effect will be better. Gypsum powder can prevent moss, which will neither dilute the pool water nor cause hypoxia in the pool water. Generally, all mosses can be killed within half a month, and the effect is better than that of copper sulfate. First, the harm of moss Moss, also known as mud moss, is a general term for several filamentous green algae such as Spirogyra, Diptera and Phaeophyta. Most of the moss in the culture pond germinates in the shallow water of the pond after the weather gets warmer, and grows into plumes, with the bottom tied at the bottom of the pond and the top standing upright in the water, so it is also called submerged filamentous plants. When aging, it leaves the bottom of the pool and floats in the water, forming a tangled silk. Fish, shrimp, crabs and other breeding animals mistakenly enter it and are often entangled in it. Lightly, a lot of moss is attached to the body surface of shrimp and crab, which affects its growth and commercial value; In severe cases, fish, shrimp, crabs and other cultured animals died of hypoxia. In addition, there are a lot of messy filaments floating in the water, which seriously affects the absorption of light energy by plankton, reduces plankton in the aquaculture pond, and causes the decrease of cultured animals; On the other hand, it hinders the rise of water temperature and the dissolution of oxygen, consumes a lot of nutrients in the water, makes the pool water dilute, causes the slow growth of cultured animals, and reduces the economic benefits of pond culture. Second, preventive measures 1, dredging: If the pond is not thoroughly cleaned, the bottom of the sludge is relatively fat, which provides sufficient nutrition for the growth of moss, and dredging will cut off its nutrient source. 2. Deepen the water level: Deepening the water level can prevent sunlight from directly hitting the bottom of the pool and cut off its energy source. 3. Algae culture: on the one hand, the transparency of the water body decreases after fertilization in the pond, and the sunlight cannot directly reach the bottom of the pond; On the other hand, algae in the water can compete for nutrients needed by moss and inhibit the growth of moss. Algae culture products can be "green and available", and the algae culture speed is fast and the effect is lasting. The most important thing is that the effect is very significant at this low temperature in spring. 3. Removal methods: There are several methods to remove moss in aquaculture ponds, such as mechanical removal, biological removal, manual removal and chemical removal, among which chemical removal and manual removal are the most commonly used. Manual cleaning method is generally aimed at the situation with a small amount of moss. The disadvantages of this method are: time-consuming and laborious, incomplete cleaning, and easy to repeat. Copper sulfate is usually used for chemical removal. However, the shortcomings of copper sulfate are still outstanding. Copper sulfate is a heavy metal salt, so it is very toxic and copper ions remain for a long time. After use, it has a great influence on the feeding and growth of cultured animals, so it can not be used continuously, otherwise it will cause the accumulation of metal ions in aquatic animals and lead to metal poisoning. Fourth, the new drug to remove moss-"Qingtaisike" in order to avoid the shortcomings of using toxic drugs such as copper sulfate and reduce the risk of breeding. After years of research, Furunde Company finally developed a new drug for removing moss at the end of last year-"Qingtisek" and "Qingtisek". Its advantages are: 1, which is scientifically compounded from various raw materials according to the growth characteristics of moss; 2. It is completely different from the action characteristics of strong toxic drugs such as copper sulfate, and adopts brand-new imported low-toxic drugs, which has little irritation to fish, shrimp and crab; 3. It has strong pertinence, has the function of selectively killing moss, and has little influence on feed grass such as grass and water peanuts in the crab pond, and has little influence on phytoplankton in the water. 4. Less dosage and convenient operation. After being dissolved in water, it can be directly sprinkled or mixed in soil, and directly dried in places with dense moss.