The pathogen is anchovy. It is mainly parasitic in the concave part at the junction of tadpole carcass and tail. The head of the worm penetrates deeply into the human tadpole tissue, and the part left outside the host body accounts for 2/5-2/3 of the whole body length. The muscle tissue of parasitic parts often appears red and swollen, erythema appears when bleeding, and ulceration and tissue necrosis appear in severe cases. Worms suck the blood and body fluids of tadpoles, and 3-4 carp anchors parasitize tadpoles, and the tail is 5-6 cm long, which will soon lead to the death of tadpoles; Parasitic 1-2 hours will not die immediately, but it will stop the growth of tadpoles.
Prevention and control methods: before tadpoles are stocked, the pond is cleaned with quicklime, which can kill anchovy larvae in the water. The treatment is soaked in potassium permanganate solution with the concentration of10-20mg/L for 2-2.5h, once a day for 2-3 consecutive times. After 2 weeks, the worms died one after another, and the tadpoles would float when they were soaked. Clear water should be used to wash away mucus and deposited trace manganese dioxide on gills to ensure normal breathing of gills. You can also spray 90% trichlorfon solution with the concentration of 0.5 mg/L in the whole pool, and the effect is good.
Tadpole management
1. The purpose of changing fresh water frequently is to adjust the water quality of tadpole pond, increase dissolved oxygen in water, enhance metabolism level and promote growth. It should be sunny to change water in tadpole pond, usually at 7-8 o'clock after the sun rises. At this time, the difference of water temperature is small, and tadpoles are exposed to the sun for a long time after changing water, which is easy to adapt to the new water body. Generally speaking, the amount of water exchanged is about half of the original amount of water in tadpole pond. When changing water in spring, summer and autumn, the water temperature of injected fresh water should be slightly lower than that of the original pool by 0.5-65438 0.0℃. If the temperature difference exceeds 3℃, the temperature should be properly adjusted to make the temperature difference less than 3℃ before changing water or slowing down the water change speed. The frequency of changing water varies with seasons, which may be once a week in spring and autumn, twice a week in summer and once every two or three weeks in winter.
2. Keep the pool water clean, and remove the suspended debris and dead tadpoles on the surface of the tadpole pool in time; To remove the residual feed on the dining table, it is best to clean the dining table every day, soak it in bleaching powder solution or lime water with the concentration of 1g/m3 for 5- 10min, and then put it back in its original place; Disinfect the water regularly, and it is best to use bleaching powder solution with water concentration of 0. 5- 1. Disinfect the whole pond with lime water with the concentration of 10-20g/m3 every 7- 10 days to ensure the water in the tadpole pond is clean.
3. Rescue the floating head of floating tadpoles in time, which is mostly a precursor, such as a disease-free tadpole suddenly reducing its food intake; The tadpole pool water suddenly turns black and turbid, and bubbles and foams often appear on the water surface and the edge of the pool; Tadpoles no longer move vertically up and down in the pool water or swallow floating feed on their backs, but float on the water without eating, fidgeting and sinking. The severity of tadpole floating head can generally be judged by naked eye observation. There is no need to panic, and there is no need to take rescue measures for frivolous heads. If the weather is sultry, rainy, windless or the wind direction turns from south to north, the temperature is often high, the air pressure is low, the oxygen consumption of organic matter increases, the water quality tends to deteriorate, and the dissolved oxygen in the water gradually decreases, which is easy to cause the floating head phenomenon of bullfrog tadpoles. Sometimes floating heads appear in the first half of the night, even in the evening or after a thunderstorm. This floating head is a heavy floating head, and measures must be taken to rescue it immediately. Fresh water should be added immediately. It is best to flush the water horizontally on the board or reed mat, and then flow into the tadpole pool. In the tadpole pond where fresh water cannot be injected temporarily, the yellow mud is 225-625kg or 7. 5- 15kg alum solution can be sprinkled all over the pond per hectare, so that a large amount of organic matter in the pond can be adsorbed and precipitated at the bottom of the pond, and the oxygen consumption of organic matter can be reduced to maintain the oxygen demand of tadpoles in the pond.
4. Promote the landing of bullfrog tadpoles in time. After the forelimbs grow out, the respiratory function of gills gradually deteriorates, and the structure and function of lungs gradually improve. At this time, bullfrog tadpoles can't live in water for a long time, but often come out of the water and board the land to breathe air to maintain the oxygen needed for their life metabolism. During the physiological metamorphosis of bullfrog tadpoles, a slight negligence in management will cause a large number of deaths. This is a dangerous period for the management of bullfrog tadpoles, also known as the peak of death. Therefore, at this stage, we should actively create conditions and give them landing conditions in time to let them land. First of all, we should lower the water level in the tadpole pond from 70-80 cm to 20-30 cm, exposing some beaches and mounds in the pond for them to land. Second, some floating objects such as wooden boards and plastic foam boards should be put in the tadpole pond, so that deformed tadpoles can board the wooden boards or foam boards to breathe the air out of the water, and the tadpoles can be safely transformed into young frogs.