In recent years, there has been frequent outbreaks of fish disease in surface waters, among which parasites and fish have the highest incidence of outbreak hemorrhage, while the latter is caused by parasites biting fish. Fish parasitism is the epidemic peak from July to October, and 500,000 to 5 million cubic meters of reservoir lakes are affected. The water area is widespread and the epidemic takes a long time, causing serious damage. The main difficulty faced in the treatment of fish diseases is that the water surface is large and the cost is high. Therefore, we will now talk about the prevention and treatment of several serious water surface parasites.
I. Symptoms and epidemiology
1. Chinese fish carp disease: Diseased fish have difficulty in breathing, are restless, have increased mucus, and the tip of the silk is white. The female Chinese scorpion fish hooks on the scorpion of the fish with a large hook. When a large amount of parasitism occurs, the scorpion has many white pods on its upper edge. It is also known as rickets. The Greater Chinese maggots only parasitize grass carp, governorfish, and red-eye turtles. Sick fish swimming around in the water or wild swim, tail fins exposed the surface of the water, it is also known as tail disease, diseased fish body weight loss, growth blocked and even death. The Chinese fish gills are widely distributed, with Heilongjiang in the north and Guangdong in the south, with a long period of prevalence, April-October as the popular season, and June-September as the epidemic peak.
2. Cysticercosis: Increased mucus count of diseased fish, full or partial paleness, difficulty breathing, significant floating seeds in the ankle, and the body is not easily visible by the naked eye. Fresh insects are visible under the microscope. Do grasshopper exercise. The body destroys the fish's cricket tissue and causes the fish to die. This is a common and frequently-occurring disease that is found throughout the country. Mainly endemic in the late spring and early summer, more endangered carp and grass carp species.
3. Anchor head fish carp disease: The insect can parasitize the whole body of the fish. The first half of the insect body penetrates into the host tissue, and the latter half is exposed outside. When the animal is severely infected, the fish body looks like it is dressed in a coat. "It is called. When infected with this disease, it causes redness and inflammation of the skin tissue, forming pomegranate-like red knots. When grass carp, carp, etc. are infected with the disease, scales are often â€œsnaggedâ€ into gaps. The diseased fish are uneasy and their appetite diminishes. There is an epidemic of this disease throughout the country.
Second, prevention methods Prevention methods: 1 improve the environment. After the winter catch or before the arrival of the spring rainy season, use lime to disinfect. The dosage is 25g to 40g/m3. At this time, less medication is used, which can save investment. 2 After disinfection, kill the insects with conventional insecticides, 90% crystal trichlorfon 0.7 g/m 3 or new insecticide, and use the dosage as indicated. 3 Disinfect the fish before the fish bath: Use 20 g/m3 of potassium permanganate to dip for 15 minutes to 20 minutes or crystal trichlorfon 500 g/m3 for 15 minutes. 4 Reasonable stocking. Excessive density or unreasonable mix will make the relative space of the fish relatively reduced, the fish excessive secretion of adrenal hormones, physical strength, thereby increasing the chance of dyeing and spreading. 5 Strengthen management, exercise caution, avoid excessive stress response, and improve the fish's own resistance.
Treatment method: 190% crystal trichlorfon 0.7 g/m3 was sprayed in the entire library. 2100 grams of trichlorfon were mixed with 30 kg of bran or compound feed and fed for 4 days.
Third, prevention and treatment experience
1. Strengthen the awareness of disease prevention: large water surface breeding investment is large, and once the incidence of losses is large, it should be based on prevention. Prevention is an active treatment. Most of the fish in the fish are infected when they have died. Treatment can only restore the less severe disease.
2. Etiological analysis: 1 Quarantine at the end of the fish species, pathogens from exotic fish species. 2 Overstocking is too large or it is unreasonable. 3 Water pollution, such as sediment not dredged or livestock and poultry manure without direct fermentation into the water.
3. In order to prevent the occurrence of bacterial diseases, they should be sterilized and sterilized immediately after the insecticide. 35g/m3 of lime water or other disinfectant drugs can also be directly used to kill the drugs.
4. When using drugs, the history of fish diseases and drug history in the waters should be considered. Some pesticides have been used in the past year, and it is best to change drugs this year.
5. Accurate measurement, scientific medication. In order to ensure efficacy, taking into account the effects of drug loss and environmental factors, the theoretical dosage should be further increased by 20%.
6. When it is difficult to use drugs for larger bodies of water, the method of attracting food can be used to concentrate the feeding of baits. Add spices such as sautÃ©ed bran and rice bran with cinnamon and mix it with food to attract fish to several fixed food areas. This facilitates local disinfection or feeding of baits. This method of feeding baits is suitable for the prevention and treatment of mild conditions.
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