Prevention and treatment of common diseases of fish in spring, such as Gill rot disease and vertical scale disease.

I. bacterial Gill rot

Pathogen: fish damage myxococcus. The cell is slender, basically the same thickness, blunt round at both ends, generally slightly curved.

Symptoms: the diseased fish are black, live alone and do not eat. There is a lot of mucus on the gills, and the Gill filaments rot with mud. When the condition is serious, the cartilage at the end of the Gill filaments is exposed, the inner epidermis of the operculum is congested, and the central epidermis is often corroded into a round transparent hole, commonly known as "open skylight". The Gill tissue bleeds and decays. Due to the destruction of Gill tissue, it is difficult for the fish to breathe and cause death. After the Gill valve of grass carp is infected with myxococcus, the pathological changes are not inflammation and hyperemia, but different degrees of decay, collapse and invasive bleeding in the affected area.

Harm objects and epidemic conditions: herring, grass carp, bighead carp and other farmed fish may occur this disease, mainly harmful to grass carp. It is rare when the water temperature is below 15 ℃. It became popular at about 20 ℃.

Prevention and control methods:

1. Prevention: the water depth of 1 meter per mu of water is sprinkled with 50 ml of "germicidal red" in the whole pool, once every 15 days. "Yukangle No. 2" was added to the feed with 0.5% and fed every 15 days. Before stocking, the seedlings were diluted with "seed soaking agent" at the ratio of 1 to 5000, and the medicine was bathed for 3 minutes for 5 minutes.

2. Treatment: 100,125ml "germicidal red" is sprinkled evenly in the whole pool with a water depth of 1 meter per mu, and the effect is better with "Yukangle No. 2" at the same time. If the condition is serious or fulminant disease occurs, use "Yukang No. 1", add 1.5% to the feed, 3-5 days as a course of treatment, continuous feeding until there is no increase in dead fish.

2. Vertical scale disease

Pathogen: Trichoderma punctatus

Symptoms: the body surface of the diseased fish is rough, some of the scales (mostly in the tail) open outward like pine balls, the base of the scales are edema, and the internal accumulation of translucent or blood-containing exudate, so that the scales also fall off. It also has symptoms such as rotten fins, hyperemia at the base of the fins, sometimes enlargement of the abdomen and exophthalmos. The diseased fish swam slowly, had difficulty breathing, turned upside down and raised their abdomen, which lasted for 2 to 3 days and died.

Harm objects and epidemic conditions: the disease mainly harms carp, crucian carp, grass carp and silver carp. It is popular every spring.

Prevention and control methods:

Prevention: (1) every time after pulling the net out of the fish in winter, immediately use "germicidal red" and sprinkle it in the whole pool according to the dosage of 50 ml per mu of water surface. (2) after thawing, sprinkle the whole pool with 50 ml of "germicidal red" at the depth of 1 meter per mu of water surface.

Treatment: every mu of water surface per meter of water depth with 100,125ml "germicidal red" the whole pool evenly sprinkled, serious illness used 2 times 3 times. In areas where fish have already been fed, 1.5% of "Yukangle No. 1" will be added to the feed for three days.

Third, acne disease

Pathogen: virus

Symptoms: at the beginning of the disease, there are many white dots on the body surface of the diseased fish, which are covered with a layer of white massive mucus. With the development of the disease, the number of white spots continues to increase, while the area of spots continues to expand, resulting in the epidermis of the focus gradually thickening, forming a paraffin-like growth, shaped like acne, so it is called "acne disease". Acne will naturally fall off when it grows to a certain extent, and then new acne will appear again in the original affected area, eventually causing the fish to lose weight and die.

Harmful objects and epidemic conditions: in pond culture, 2-year-old carp were mainly harmed before and after overwintering, usually from autumn to early winter and spring, and the water temperature appeared at 10-15 ℃. Due to the low incidence and no infection of other fish in the same pond, people failed to pay attention to the disease. In recent years, due to the vigorous development of cage high-density culture technology, the disease is becoming more and more serious, and the incidence is also gradually increasing. 、

Prevention and control methods:

1. After the beginning of spring, each mu of water surface per meter of water depth is diluted with 50ml "germicidal red" or 20000ml (0.3~0.6ppm) of "highly effective sterilized iodine" and sprinkled throughout the pond. Use once a week to control the number of viruses in the water.

2. After fish feeding, 2 ‰ of super-concentrated photosynthetic bacteria and 0.3% of high stability and easy reduction of Vc were added to the feed to improve the immunity of fish.

Water mildew

Pathogen: water mold

Symptoms: water mildew is commonly known as white disease, skin mildew. When the water mold is first parasitized, there is generally no abnormality in the diseased fish. when the disease is seen, the mycelium has invaded the wound of the fish and grows outward. If the fish is injured due to careless operation and transportation, frostbite caused by low temperature, or primary focus caused by parasite or bacterial infection, the motile spores of the mold invade from the wound of the fish, absorb nutrients from the skin, propagate rapidly and spread in the injured focus. grow into cotton-like hyphae. The hypha wound and adhered to the cell tissue of the wound, resulting in skin ulceration and tissue necrosis. at the same time, with the expansion of the focus area, the fish body was overburdened, swimming disorder, loss of appetite, weight loss, and finally died of illness.

Harmful objects and epidemic conditions: the disease occurred in the low water temperature season of less than 20 ℃, and was most popular in early spring and late winter. It happens all over the country. Water mold has no strict selectivity to parasites, and all farmed fish can be infected from eggs to adults. Close-raised overwintering ponds, spring pond water thin or hungry fish, are vulnerable to water mildew.

Prevention and control methods:

Prevention: fish entering the pond should be operated as carefully as possible so as not to injure the fish. Before entering the pool, use the "seedling soaking agent" according to the proportion of 1 stroke 5000, then enter the pool after 3 minutes of medicine bath, and sprinkle it with "germicidal red" according to the water depth of 50 ml per mu of water surface. Avoid handling farmed fish below 15 ℃ to avoid frostbite and abrasion.

Treatment: water depth of 1 meter per mu of water is sprinkled with "germicidal red" 100,125ml in the whole pool.

5. Cucumber disease

Pathogen: many small melon insects.

Symptoms: when a large number of parasites are parasitized, it is visible to the naked eye that the fish's body surface, fins and gills are covered with white dot cysts, so it is also called "white spot disease". In severe infection, the parasite invades the skin and Gill epidermis of the fish, causing the proliferation of the focus tissue and secreting a large amount of mucus, forming a white film covering the surface of the focus, while the focus of the fin is damaged and rotted.

Harmful objects and epidemic conditions: the disease occurred in all breeding areas in China. This insect has no strict selectivity to the host and does the most serious harm to the fish species in that year. The disease can be infected no matter in what kind of breeding waters.

Prevention and treatment:

1. Before stocking, the water depth of 1 meter per mu of water is dissolved with 50 grams of "fish and insect pests 2B" 2000 times water, and then sprinkled in the whole pond. "Yukangle No. 2" was added to the feed with 0.5% and fed every 15 days. Before stocking, use "seedling soaking agent" according to the ratio of 1 to 5000 and then take a medicine bath for 3 minutes for 5 minutes.

2. After dissolving with 50 grams of fish and insect 2B2000 in double water, sprinkle it evenly in the whole pond according to the water depth of 1 meter per mu of water surface and use it again every 2 days. At the same time, it works better with "Yukangle No. 2". If the focus is seriously infected, "Yukangle No. 1" is added to the feed by 1.5% and fed continuously for 3 to 5 days.