Prevention and treatment methods for common intestinal diseases in fish

I. Viral intestinal diseases: enteritis. Harmful targets: grass carp, black carp. Symptoms: the diseased fish has a darkened body color, red and swollen anus, and in severe cases congestion at the base of the fins, red spots on the abdomen, and inflammation of the intestinal tract, which appears red or purplish red. Prevention and treatment methods: ① Before stocking fingerlings, bathe them in 10 ppm bleaching powder. ② During the epidemic season, splash 1 ppm bleaching powder over the whole pond once every half month, or feed sulfonamide medicated bait. ③ Garlic treatment. Use 250 g of garlic per 250 kg of fingerlings, mix it into the bait, and continue for 3 days to 6 days.

II. Parasitic intestinal diseases 1. Coccidiosis. Pathogen: Eimeria. Harmful targets: black carp. Symptoms: the gills are pale, many grayish-white "tumors" form on the inner wall of the intestinal tract, the tissue around the lesions ulcerates, and white pus is produced. Prevention and treatment methods: ① Thoroughly clear the pond with quicklime. ② Feed iodine solution medicated bait. Use 30 mL of 4% iodine solution per 250 kg of black carp, for 4 consecutive days. ③ Feed sulfur powder medicated bait. Use 50 g of the medicine per 250 kg of black carp. 2. Myxosporidiosis. Pathogen: Myxobolus. Harmful targets: common carp, crucian carp. Symptoms: white spot-like cysts form on the intestinal mucosa. In common carp and crucian carp over 2 years of age, the cysts can also pass through the intestinal wall and appear in large numbers on the outer wall of the intestine. Prevention and treatment methods: ① Remove diseased fish promptly, and bury them deeply after death. ② Strictly clear the pond, and regularly disinfect fishing gear and feeding utensils. ③ Before stocking fingerlings, soak them for 30 minutes in 500 ppm potassium permanganate solution or 500 ppm calcium cyanamide turbid liquid. 3. Side-sporocystiasis. Pathogen: Asymphylodora japonica. Harmful targets: black carp, common carp, crucian carp. Symptoms: the diseased fish has a darkened body, swims slowly, and floats in groups on the downwind water surface. Fry or summer fingerlings can die in large numbers 3 days to 5 days after onset. Prevention and treatment methods: ① Thoroughly clear the pond and kill snails. ② Do not use ponds that were used to raise adult fish in previous years for fry and summer fingerlings. 4. Bothriocephalosis. Pathogen: Bothriocephalus gowkongensis. Harmful targets: grass carp, black carp, silver carp, and other fish of the year. Symptoms: the diseased fish gradually becomes emaciated, stops feeding, and often keeps its mouth open; at the bend of the rear foregut, there are many thin noodle-like white worms, which can cause mass death of fingerlings. Prevention and treatment methods: ① Clear the pond with quicklime or bleaching powder. ② Bury dead fish far from the pond. ③ Feed trichlorfon medicated bait. Mix 50 g of 90% trichlorfon crystals with 500 g of flour and feed continuously for 3 days to 6 days. Stop feeding for 1 day before administering the medicine. ④ Feed pumpkin seed medicated bait. Grind 250 g of pumpkin seeds into powder, then mix thoroughly with 500 g of flour and 500 g of rice bran, and feed continuously for 3 days. 5. Ligulosis. Pathogen: Ligula. Harmful targets: common carp, crucian carp, silver carp, bighead carp, grass carp. Symptoms: the diseased fish has a large abdomen and a thin back; when pressed lightly by hand, it feels hard. Prevention and treatment methods: ① In spring, dry the pond bottom in the sun and clear the pond with quicklime. ② Drive away and kill gulls and birds to cut off the developmental cycle. 6. Capillariasis. Pathogen: Capillaria nematode. Harmful targets are broad. Symptoms: it is highly harmful to summer fingerlings and can cause loss of appetite, emaciation, and gradual death. Prevention and treatment methods: ① Clear the pond with quicklime. ② Feed crystalline trichlorfon medicated bait. Mix 90% crystalline trichlorfon at 5 g-7 g per 250 kg of fingerlings into the bait, and feed continuously for 6 days.