The ice in most ponds and reservoirs in Jilin Province began to melt in April. As the temperature rises, this month is often the season for fish diseases. If it does not cause Attaching great importance to and taking preventive measures will bring a great threat to our province’s aquaculture fishery and cause huge economic losses. The symptoms and prevention methods are analyzed as follows:
1. Illness prediction
is also called white hair disease. The common types of pathogens include water mold and cotton mold. The symptoms are:white cotton-like mycelium can be seen with the naked eye, or brown attachments such as mud particles can be seen, which makes the fish body overloaded, swims abnormally, loses appetite, becomes thinner, and eventually leads to death. Grass, yong, silver carp, carp, Qing and other fish are susceptible to this disease.
(2) Vertical scale disease
is also known as scale disease and loose scale disease. The pathogen is initially believed to be the water-type Punctate P. mucilaginous. The symptoms are:the fish’s scales are partially or completely firm and open like pine cones, and the squamous cysts at the base of the scales are edema. When the scales are pressed with the fingers, there will be tissue fluid ejected from the squamous sacs, and the scales will fall off. Sometimes it is accompanied by hyperemia of the skin surface of the fin base, protruding eyeballs, abdominal swelling, and ascites. Sick fish swim slowly, have difficulty breathing, turn their body sideways, and have their abdomen upward. If it is not treated in time, it will die if it lasts for about 2-3 days. This disease mainly harms common carp and crucian carp. Grass chain and bighead carp occasionally occur.
(three) oblique tube worm disease
This disease is the parasitic tubeworm parasites on the gills and body surface of fish. Large amounts of parasitic can cause the skin and gills to produce a large amount of mucus, forming pale mucus on the body surface.
Layer, tissue is destroyed, breathing is difficult. During the spring and early winter seasons, if the water temperature and environmental conditions are appropriate, pathogens will multiply, and a large number of diseased fish will die within 2 to 3 days. In recent years, this disease has often occurred in aquaculture and fisheries in various regions of our province. It causes a large number of fish deaths and is one of the serious spring diseases in northern regions.
2. Prevention measures
(1) Preventive measures
1. Water mold disease is mainly caused by careless handling during fishing and transportation, causing fish body injury, or parasite invasion and damage to the skin, accompanied by crowded fish and water quality Caused by pollution. Since most of the fish farming areas in our province put fish species in spring, and also need to carry out fishing and transportation, it is inevitable that the fish will be damaged. Therefore, in operations such as pulling nets, transporting, and putting fish, it is necessary to be as careful as possible to reduce fish body injuries. This is the most effective way to prevent the occurrence of this disease. After pulling the net, use disinfectant to splash it to avoid fungal infection.
2. Vertical scale disease is mainly caused by accidental operations such as fishing, transportation, and stocking, which injures the fish body and causes bacteria to invade by opportunity. It is recommended to standardize the operation as much as possible when pulling the net and stocking. Use iodine preparations for prevention in time after Kaihua to avoid bacterial invasion.
3. Oblique tubeworm disease should be controlled as far as possible from the pathogen. First of all, the breeding pond should be disinfected with tools; adjust the water quality in time or add new water. If the bottom silt is too thick and the bottom of the pond is not clear all the year round, the pond should be cleaned and silt removed. Purchase quarantined fry and fingerlings to effectively prevent the spread of parasitic diseases.
(2) Treatment measures
1. Water mold
Povidone-iodine or fishery medicine with high iodine content should be used in the whole pond for povidone-iodine or fishery medicine with high iodine content, or a large dose of chlorine dioxide with high chlorine content should be used in the whole pond Sprinkle, so that fish diseases can be effectively controlled.
2. Vertical scale disease
The disease can be treated in spring with the same treatment as saprolegnia. If the pond has already been fed, enrofloxacin and other drugs can also be added to the feed Mix bait and feed, and use vitamin C at the same time to improve the fish’s own immunity, so that the disease can be effectively controlled as soon as possible.
3. Oblique tube worm disease
oblique tubeworm disease should first be treated from the pathogen, first to kill the insects and then sterilize. Use the national standard fishery medicine copper sulfate and ferrous sulfate mixture to splash the whole pond. After an interval of 1-2 days, use iodine-containing preparations to disinfect the whole pond to prevent secondary infection of bacterial diseases. If the disease does not kill the pathogen, it is easy to recur. Therefore, regular microscopic examinations should be taken in the treatment to ensure that the pathogen is killed while using bactericidal drugs to consolidate the treatment until recovery.