Disease prevention and control techniques of mandarin fish

Mandarin fish, also known as Mandarin Fish, sweet-scented osmanthus fish, ao fish, ridged flower fish, fat mandarin fish, etc., are only distributed in the rivers and lakes of the eastern plain of China, overwintering in the depths of the water in winter, swimming to shallow water in spring, daytime and night out, ferocious sex, young fish like to eat fish and shrimp, adult fish to eat fish mainly, stop feeding in winter, and now realize artificial breeding, let's take a look at the disease prevention and control technology of mandarin fish.

Water mildew

[cause of the disease] in the process of mandarin fish breeding, if the hatching water of fertilized eggs is mixed with dirt, the fish eggs will be damaged and infected with water mold. Infected fish eggs, naked eye observation of the egg membrane has villi, similar to the "domestic fish" egg water mildew, serious will cause a large number of deaths.

[characteristics of the disease] White floc was found on the body surface and abrasions of diseased fish with naked eyes. Once suffering from the disease, the diseased fish swim slowly, lose appetite, and finally lose weight and die.

[control methods] the hatching water of mandarin fish by ① was filtered with 60 mesh nylon silk net to prevent sundries from entering. ② sprinkled with 0.01% malachite green solution, stopped water for 3 minutes, 2 times a day, or sprinkled with 2% salt water for 5 minutes. ③ do not choose injured fish as parent fish. Before the parent fish goes into the pond, smear the fish with 1% malachite green ointment or an appropriate amount of sulfonamide ointment. ④ can soak the fry, fry and adult fish for 5 minutes with 3% salt water for 10 minutes, or wash the diseased fish with 1% salt water and a few drops of vinegar for 5 minutes. In addition, fish body abrasions are prevented in the process of fishing and transportation.

Ciliosis

[incidence characteristics] ciliosis is one of the main diseases in the process of summer flower cultivation of mandarin fish. Rotifers are parasitic on the body surface, fin and head of mandarin fish. The disease spreads rapidly, when the number of parasites is small, it has little effect on the activity of fish; when the number of parasites is large, fish refuse to eat. It is visible to the naked eye that there are white spots on the fish, the mouth cannot be closed, swimming is out of balance, and then die. The disease is extremely harmful.

[prevention and treatment methods] ① can play a role in prevention and treatment by splashing the whole pool with 3% salt water once a day and stopping water for 3-5 minutes. ② convection tank was sprinkled with 1.6 × 10 ~ (- 6) copper sulfate and ferrous sulfate (5 ∶ 2) mixture and stopped water for 3 minutes. The mixture of copper sulfate and ferrous sulfate (5 ∶ 2) was sprinkled throughout the pool. When ③ summer flowers go down to the pond, wash the diseased fish with 2% salt water for 2 minutes.

Anchor head scrofula and Chinese disease

[disease characteristics] Anchor head mackerel is mainly parasitic on the body surface of mandarin fish, which makes the fish lose weight and lose the ability to swim and prey. The Chinese mackerel is mainly parasitic on the Gill, destroying the Gill tissue and affecting the respiratory ability. This kind of fish is mainly harmful to mandarin fish, and the harm is greater. If two anchor heads are parasitized on a juvenile fish of 5 cm, it can lead to the death of juvenile fish, so it should be prevented as soon as possible in culture.

[prevention and control methods] the application of quicklime to clear the pond before the release of ① seedlings can kill the fish in the water, and pay attention to the cleaning of water source and feed at any time to reduce the source of infection. The bait fish of ② mandarin fish can be washed with 15 mg / L potassium permanganate for 2 hours to eliminate the fish. ③ can soak the mandarin fish with 5mg / kg crystal trichlorfon solution for 5 minutes, or sprinkle it in the whole pool. Mg / kg crystal trichlorfon can make the fish shedding.

Rotten Gill and enteritis

[characteristics of the disease] most of the disease occurs in the high temperature season, with white spots and dirt and mucus attached to the Gill filaments.

[prevention and treatment] Gill rot can be washed with 2 mg mercurous nitrate solution per liter for 10 minutes, which can gradually alleviate the disease. The main symptoms of enteritis are congestion, redness and swelling from rectum to anus, light yellow stool, and in severe cases, the whole intestine is swollen and purplish red, and the feces are concentrated. The main cause is that bait fish carry bacteria and are swallowed by mandarin fish. Therefore, the method of prevention is to disinfect the bait fish, wash the fish with 10% salt water, and remove the sick and disabled bait fish in time to eliminate the source of infection.

Purulent disease

[characteristics of the disease] Chinese oysters are parasitic on the body surface, fins and gills of mandarin fish, and bedbug-sized insects can be seen with the naked eye. They often stab the parasitic fish with their barbed thorns, causing diseased fish to swim wildly and restlessly.

[control method] the disease can be cured by sprinkling the whole pool with crystal trichlorfon (90%) so that the concentration of pool water reaches 0.3 × 10 ~ 6 × 10 ~ 6 and 0.5 × 10 ~ 6. In the prevention and control of mandarin fish disease, it should be noted that mandarin fish are very sensitive to drugs, especially trichlorfon, the concentration used must be strictly controlled, the concentration is too high to cause fish death.

Rotifer disease

[induced pathogen] many species of rotifers and rotifers.

[disease characteristics] groups of diseased fish swim wildly along the edge of the pond, do not eat, the body is thin, commonly known as "horse racing disease". There is sometimes a layer of white on the surface of the fish.

[diagnostic method] when the small fish are observed under an anatomical microscope, it can be seen that there are a large number of rotifers on the body surface of the diseased fish, especially on the head and fins. When a small amount of Gill filaments were observed under the microscope, it was found that a large number of rotifers were concentrated on the Gill filaments, destroying Gill tissue and seriously affecting Gill respiration.

[hazard characteristics] breeding farms are popular all over the country, especially in the Yangtze River and Xijiang River basins. The epidemic season of the disease is from May to August every year, especially from June to July. The disease is extremely harmful to mandarin fish fry, and it is one of the most harmful diseases in mandarin fish fry breeding stage, especially in close culture.

[control methods] within 10 days after hatching, the fish were bathed in the mixture of copper sulfate and ferrous sulfate (5:2) of 7ppm for 10 minutes, once a day. In other stages, the mixture of 0.7PPm copper sulfate and ferrous sulfate (5:2) was sprayed all over the pool, and the curative effect was remarkable.