<b>(Video of the wheelworm in the microscope field of view</b>).
Wheelworm disease is a fish disease that is more prevalent and harmful in fish farming production and is not easy to diagnose, and it occurs in fish farming areas throughout the country, causing fishery production to suffer greater losses every year.
Rotiferosis is caused by the large number of rotifers parasitizing the skin or gills of the fish, and microscopic examination of the gills can often see that the insect body is densely packed all over the gills. There are about 10 kinds of pathogens that cause wheelworm disease, mainly significant wheelworm, coarse spiny wheelworm, Chinese Du's wheelworm, spherical wheel worm and Meixi small wheel worm, etc., all belong to the order Officer, swimming suborder, pot-shaped family, the size of the insect is 20-40 microns. Wheel worms look at the felt hat on the side and round butterflies on the reverse side, and when they move, they are like wheels turning, so they are called wheel worms.
<b>1. Pathogens</b>
Wheelworm disease is a ciliary disease caused by wheelworms and small wheelworms that mainly parasitize fish gills or skin.
<b>Second, the symptoms of wheelworm disease</b>
The insect body that causes the occurrence of wheelworm disease in fish mainly parasitizes the surface part of the skin, fins and gills of the fish body that are in contact with the water body, mainly parasitizing the gills of the fish, the insect body takes the skin and gill tissue of the host as nutrition, and the diseased tissue is stimulated to secrete too much mucus, which makes the gill tissue ulcerate when severe, affecting the breathing and normal activities of the fish.
Sick fish infected with wheelworms, body color black, poor feeding, weak physique, swimming alone, swimming slowly, sometimes there are "white heads and white mouths" pathology, and sometimes swam wildly around the pool in groups, showing a "running horse" shape. Sometimes it can be seen that the surface of the fish body is white, the mucus secretion on the gills of the fish becomes more, some of the fish body will be partially whitened, the gill silk epithelial tissue of the fish body will grow, the gill silk tissue will be swollen or destroyed, etc. When a large number of parasitic wheelworms are born, the normal breathing and activity of the fish gills are seriously affected, resulting in suffocation and death of the fish.
<b>Third, the prevalence and harm of diseases</b>
Farmed fish rotiferosis is a common parasitic disease, and its prevalence is very widespread, generally occurring in early spring, early summer and during the wintering period. The damage of wheelworms mainly occurs in the fry, fingerling stage of fish, the peak season of the epidemic is April-August, and the water temperature is 18-28 ° C. Especially when the pond culture density is large and the water quality is too fat, it is more likely to produce infection. When the fish body is parasitized in large quantities by rotifers, a large number of fish deaths occur. Therefore, once the fish body finds the wheel worm, it should take timely treatment measures to avoid major losses.
<b>Fourth, the prevention and treatment of wheelworm disease</b>
Follow the principle of "prevention first, prevention and control combined".
<b>(1) Preventive measures</b>
1. Thoroughly clean the pond and disinfect it.
Quicklime and bleach powders are commonly used.
<b>(1) Quicklime clearing pond method</b>
Dry method of clearing the pond method: first put the dry pond water or leave the bottom water depth of the fish pond about 7-10 cm, each mu of fish pond with block quicklime 120-150 pounds, the block quicklime water is fully dissolved and diverged, while the lime water on the pond bottom and pond wall is evenly sprinkled on the whole pond, when conditions permit, you can also use tools to flip the bottom of the pond the next day, so that the pond bottom silt and lime water are fully mixed, in order to enhance the disinfection effect of the pond. Under normal circumstances, after 7-10 days, the medicinal effect of quicklime basically disappears, and you can inject water to release fish.
With water clear pond method: for some ponds that cannot be completely drained, the method of clearing ponds with water can be used, that is, the pond is 250-300 kg of quicklime per mu/1 meter water depth, and the block quicklime is fully dissolved and diverged with water, and it is not waited for it to cool, and the pond is immediately sprinkled evenly while it is hot. Usually, the medicinal effect of 8-10 natural lime disappears, and at this time, fry can be released into the pond for fish culture.
<b>(2) Bleaching powder clear pond method</b>
Pond per mu / m water depth with chlorine 30% bleach powder 27-40 kg (about 35 kg), with plastic or barrel water fully dissolved after the whole pond evenly sprinkled, generally after 5-8 days after the pond can be stocked with fish fry for fish production.
2. For seedlings, 0.7 grams of copper sulfate per cubic meter of water can be used for prevention.
3. In the case of water temperature of 15-20 °C, each cubic meter of water body is prepared with 8 grams of copper sulfate to make a solution, soak the seedlings for 10-20 minutes, and the soaking time depends on the tolerance of the fish.
4. In the pond with a depth of 1 meter per acre, soak in the pond evenly with 30 pounds of neem branches and leaves (if the pond is larger, you can tie a few more bundles, the specific number of bundles depends on the size of the pond), replace once a week, and use it 3-5 times continuously.
5. Before stocking, soak in 10-20ppm potassium permanganate solution for 10-30 minutes.
<b>(2) Therapeutic measures</b>
1, each cubic meter of water with copper sulfate 0.7-1 grams or 0.7 grams of copper sulfate and ferrous sulfate compound (5:2) evenly sprinkled in the whole pool, for fish ponds with severe wheel worm disease, can be used continuously for 2-3 times.
Note: Copper sulfate is more toxic, and the water measurement error and other reasons, so after taking the drug should pay attention to observe the activity of the fish, if found abnormal, should immediately start the aerator or add and change the pond water.
2. The diseased fish should be soaked in 2% to 3% salt water for about 5 minutes, and the specific and flexible grasp according to the temperature and the tolerance of the fish body.
3. The diseased fish pond can be sprinkled evenly throughout the pond with 0.3-0.5ppm of enemy insects.
4, each acre of water depth of 1 meter with maple poplar leaves 50-60 kg of decoction juice evenly sprinkled throughout the pool.
5, each acre of water depth of 1 meter with neem branches and leaves 50-60 pounds of boiling water or beating evenly sprinkled throughout the pool.
6, 1 meter per acre of water depth with raw leeks 6-10 catties, mashed after adding 0.5 kg of salt, mix well and then sprinkle the whole pool.
7, each cubic water body with matrine solution 0.4 grams, diluted after uniform whole tank sprinkling 1-2 times.
8, per acre of water depth of 1 meter with benzalkonium bromide solution 50-100 grams, add water to dilute the whole tank sprinkled, polyculture according to 20 ml dilution after the whole tank spilled.
9, copper ferrous sulfate compound (5:2) 0.7 g / cubic meter plus avermectin solution (1%) 15 ml / mu / m mixed whole tank sprinkled.
10, 25 ml / m3 formalin sprinkled throughout the pool.
11. At present, there are many fish insecticides in the fish drug market that use high-tech compound combinations, which have a good effect and can be selected according to the actual situation. For example, insecticide drugs such as cypermethrin and cypermethrin. Insecticidal plant medicines can be soaked with sap such as pine branches and leaves.