Prevention and treatment of three major diseases of pond fish in spring and summer

1 carp hemorrhagic disease

1.1 symptoms and etiology

Under the scales of the abdomen of the diseased fish, the fins and tail stalks are congested and red, and the diseased fish float close to the ice or float on the surface of the water, swim slowly along the edge of the pool in groups and gradually die.

① hemorrhagic septicemia. The appearance of the diseased fish is normal or the abdominal scales are congested and red. Blood appears in the body cavity when dissecting the diseased fish, and there are congestion spots in the internal organs. The disease is caused by Aeromonas hydrophila.

② brown disease (hemorrhagic Gill disease). The filaments of the diseased fish are swollen, the color is dark, and some of the filaments form aneurysms. When the illness is serious, the blood is brown, and the phenomenon of floating head also occurs when the dissolved oxygen in the pool water is sufficient. The disease is caused by excessive contents of ammonia, nitrogen and nitrite in pool water.

③ occult hemorrhagic disease. When the diseased fish first came out of the water, the body color was normal and the body surface mucus was less; after being trapped in the cage for 2 or 3 hours, the body surface appeared hyperemia. A small number of fish have red upper jaw (red lips); after being trapped for 7 hours, the diseased fish begin to die one after another. During dissection, the diseased fish liver showed fatty liver or flowering liver, bold or only gallbladder (also known as gallbladder). The disease is caused by blindly feeding high-protein feed for a long time and low protein utilization rate.

④ dominant hemorrhagic disease. The abdominal scales, caudal stalk and cheek cover of the diseased fish are congested, and the caudal and dorsal fins are blood red. During dissection, muscle congestion, liver enlargement, light color, gallbladder enlargement and light color could be seen. The etiology is the same as occult hemorrhagic disease.

1.2 Prevention and control methods

Carp hemorrhagic disease is difficult to cure in spring, and the course of disease is longer, generally detected and treated in summer and autumn.

① improves the water environment. Divide the pond or change the water early, and sprinkle the quicklime solution or dry zeolite powder regularly.

② salt bath. 5 minutes before each feeding, the 3~4kg salt was dissolved in water and sprinkled around the feed table, sprinkling once or twice a day. The effect is better if it is carried out at the same time as feeding bait.

③ fish fingerling was sterilized. When the fish are released, if there are no other diseases, it is best to soak in 5% salt and baking soda (3 ∶ 2) aqueous solution for 5 minutes for 10 minutes.

④ fortified feed to promote physical recovery. Trace elements or drugs such as vitamin E, vitamin C, vitamin B1, vitamin B3, vitamin B6, vitamin B12, choline and Baixue powder were added to the feed before overwintering, with or without mineral additives.

2Vertical scale disease

2.1 symptoms and etiology

The scales of the diseased fish open outward, the shape of the fish is pine ball, the base of the scale is edema, and there is stagnant water or effusion with blood after a little extrusion. The disease is often complicated with ascites, with exophthalmos, sometimes bleeding at the base of the fin and on the surface of the skin, dilated abdomen and a large amount of water in the abdominal cavity. The diseased fish swam slowly, had difficulty breathing, turned upside down and died after 2-3 days. The disease is caused by Pseudomonas punctatus.

2.2 Prevention and control methods

① improves the water environment. Divide the pond early or change the water, and sprinkle the quicklime solution regularly throughout the pond during the culture period.

② fish fingerling was sterilized. Soak the diseased fish in a mixed aqueous solution of 5% salt and baking soda (the ratio is 2 ∶ 3) for 10 minutes for 15 minutes.

Disinfect ③ pool water. The fish species were sprinkled with bleach solution twice in the whole pond (the drug concentration in the pond water was 1ppm).

④ was given bait. Each 100kg fish was fed with 5g antibiotics per day for 7 days. The effect of disinfection with salt in the food market is better.

⑤ should operate briskly. Operate briskly in separate ponds or transportation to avoid fish injuries as far as possible.

(3) primitive Gill rot disease

3.1 symptoms and etiology

After the deicing of the overwintering pond in early spring, the fish species often swim in clusters on the edge of the pool or downwind, and the disease often causes the sudden death of fish species. The diseased fish floated on the surface in sunny days, showing anoxic floating head, and did not go to the bait table or ate for a while and then dispersed and floated on the surface one after another, with obvious loss of appetite and slow growth. When the Gill cover of the diseased fish is opened, tissue hyperplasia and mucus increase can be seen. The disease is caused by a large number of protozoa such as rotifer, Gill Cryptospira, Trichuris obliquus, calicium and so on.

3.2 Prevention and control methods

① is symptomatic to kill insects. When the autumn fillet species are merged into the overwintering pond or the spring fillet sub-pond, the fish species are soaked with the corresponding insecticidal aqueous solution.

② is sprinkled all over the pool. After 2-3 days of disinfection of the pool water, the whole pool was sprinkled with chlorine to prevent the focus from secondary infection with other bacterial diseases.

③ improves the water environment. The water quality of the pond is regulated by regularly sprinkling quicklime aqueous solution or dry zeolite powder.

④ was given body surface insecticidal drugs internally. Insecticidal drugs are regularly added to the feed to prevent the breeding of parasites on the body surface (including Gill).