Yrichodian is a genus of protozoa phylum, ciliary subphylum, oligomeric cilia, marginal hair, and pot-shaped family. About 200 species have been reported in this genus, and the common species parasitic on freshwater fish in China are: Du's wheelworm, Oriental wheelworm, oval wheelworm, tiny wheelworm, spherical wheelworm. Microscopic observation of the insect body, the size of 20 ~ 40 microns, the side view of the insect body like a felt hat, the reverse side of the round butterfly, the movement like a wheel rotation, high magnification mirror can see the cilia on both sides of the mouth groove.
Based on the situation in various places, the author believes that there are eight misunderstandings in the understanding of wheel worms.
<h1>First, the host occurrence stage is wrong. </h1>
Most contractors believe that wheelworms only occur in the fry and fingerling stages, and that adult fish will not become infected with the disease or even die. Wheel worm disease in places such as the Long March Fishery in our city is manifested in adult fish, especially grass carp.
<h1>Second, there is a misunderstanding of symptoms. </h1>
Where the surface of the fish is parasitic, a large amount of mucus will be secreted, and a layer of white hair will appear on the surface of the head, showing a white head and white mouth, which is mistaken for white head white mouth disease; when the gills are parasitic, the gills are swollen, secreting a large amount of mucus, which is mistaken for rotten gill disease; the dark floating head of the sick fish is mistaken for water hypoxia; the diseased fish swims wildly along the edge of the pond in a "running horse" shape, mistaken for diseases such as small trichonus algae poisoning.
<h1>Third, when it is popular, it is wrong to ask about understanding. </h1>
It is generally believed that wheelworm disease only occurs in the spring, and a large number of sick fish die in April and July, in fact, wheelworms can occur all year round, and wheelworms cause a large number of fish deaths after autumn.
<h1>Fourth, there is a misunderstanding of the transmission route. </h1>
Wheelworms are transmitted by direct contact with fish bodies, but wheelworms that leave the fish body can swim in the water, transfer the host, and can spread with water, aquatic organisms and tools.
<h1>Fifth, there is insufficient understanding of the site where the lesion is produced. </h1>
Rotifers parasitize on the surface of the fish, gills, etc., and sometimes in the nostrils, bladder and ureters and produce lesions.
<h1>Sixth, it is an error in judgment based on the physique of the fish. </h1>
Fish with poor constitution are easy to infect, but when the water environment is very poor, fish with better physique can also be infected.
<h1>Seventh, there is a misunderstanding of the infected variety. </h1>
The four major fish are difficult to resist the wheel worm, and the tilapia with strong vitality, few diseases and low oxygen tolerance, as well as the spotted forktail carp, yellow eel, loach and other species are also difficult to escape its "claws".
<h1>Eighth, there is a wrong understanding of medication. </h1>
Wheelworm parasitism in the gills as rotten gills treatment, resulting in long-term incurable treatment; alkaline water quality with copper sulfate, ferrous sulfate compound effect is very poor, and some wheelworm drugs need to adjust the water quality to alkaline to see the effect; bad weather, irritating drugs can make the disease of the sick fish aggravate the disease, resulting in a big mistake.
There are many reasons for the outbreak of wheelworms, such as shallow pool water, poor water quality, insufficient feed, over-stocking, continuous rain and other factors can induce disasters. To this end, we must improve our ideological understanding, careful management, and careful operation. From dredging ponds to improving the bottom of ponds, from fertilizer to regulating water quality and balancing algal phases, from determining stocking to baiting and disease prevention, every link must be taken seriously. At the same time, in the process of breeding, we must avoid misunderstandings in understanding, do prevention as early as possible, comprehensive prevention and control, and specifically achieve the following three points.
<h1>1． Improves fish resistance. </h1>
When a poorly constructed fish is parasitized by a rotifer, its own immune system is unable to resist, and it immediately develops symptoms of weakness, followed by death. Strengthening nutrition is the only way to enhance the physique of fish. Fish fry stage should pay attention to the rationality of feed nutrition, both to ensure the protein content of the feed, but also to ensure the balance of other essential ingredients, to avoid causing indigestion of the fish body, the physique becomes weak; after the fish enter the winter, we must pay attention to the rapid recovery of the physique, when the fish begin to feed, to choose high-quality compound feed, strengthen nutrition, feeding to do a small amount of times, while regularly adding a part of the nutrition and immunomodulators to the feed.
<h1>2． Improve the water quality environment. </h1>
During the wintering period, due to less water change, all kinds of aquatic biological metabolites accumulate in the water, after the water temperature rises, the metabolites will consume a lot of oxygen in the water, and when the oxygen is insufficient, a large number of toxic intermediates will be generated, increasing the chance of fish infected with diseases. Therefore, after entering the spring, in addition to properly changing the water and opening the aerator frequently, water quality improvers and disinfectants can be used regularly, such as "substrate net" once every 10 to 15 days, and "water-friendly agents" and other water quality improvement drugs once every 15 to 20 days to improve the living environment of fish.
<h1>3． Kill the parasites early. </h1>
In the breeding process, five steps can be done to avoid disasters.
First sprinkle the whole pool with 200 g/m 3 quicklime water
Secondly, before the fish species enter the pond, soak in 8 mg/L copper sulfate solution for 20 to 30 minutes
The third use of copper sulfate, ferrous sulfate compound hanging bag
Fourth, use efficient and pollution-free drugs to completely kill the wheelworms carried by the wintering fish
Fifth, when there is an outbreak of wheel worm disease, in addition to the use of pollution-free special wheel worm drugs, it is also necessary to choose non-irritating disinfection drugs to completely prevent and control the harm caused by wheel worms.
( Sun Save)