Common Types of Parasitic Intestinal Diseases in Fish and Their Prevention and Treatment Methods
The intestine is the main digestive organ of aquatic animals, especially for stomachless fish. The intestine is often the first barrier against anti-nutritional factors and toxic and harmful substances in feed entering the fish body, and it is the “starting point” of damage caused by anti-nutritional factors in feed to related tissues and organs of fish. If a fish suffers from intestinal diseases and the treatment is ineffective, its yield will be affected. So what are the common parasitic intestinal diseases in fish? How to prevent and treat them?
I. Common parasitic intestinal diseases in fish
1. Coccidiosis
Pathogen: Eimeria.
Affected species: 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.
2. Intestinal disease caused by side-spined trematodes
Pathogen: Asymphylodora japonica.
Affected species: 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 fry fingerlings may die in large numbers after 3-5 days of disease onset.
3. Intestinal disease caused by myxosporeans
Pathogen: Myxosporea.
Affected species: common carp, crucian carp.
Symptoms: white dot-like cysts form on the intestinal mucosa. In common carp and crucian carp over two years old, the cysts can also pass through the intestinal wall, and large numbers of cysts appear on the outer wall of the intestine.
4. Intestinal disease caused by head-groove tapeworms
Pathogen: Bothriocephalus gowkongensis.
Affected species: grass carp, black carp, silver carp and other fingerlings of the current year.
Symptoms: the diseased fish gradually becomes thin, stops feeding, and keeps its mouth open; at the bend of the posterior foregut, there are many thin noodle-like white worms, which can cause mass death of fingerlings.
II. How to prevent and treat parasitic intestinal diseases in fish?
1. Prevention and treatment methods for coccidiosis
Feed medicated bait with iodine solution. For every 250 kg of black carp, use 30 mL of 4% iodine solution, for 4 consecutive days.
Feed medicated bait with sulfur powder. For every 250 kg of black carp, use 50 g of the drug.
Use relevant deworming drugs.
2. Prevention and treatment methods for intestinal disease caused by side-spined trematodes
Polyculturing black carp to eat the river snails (intermediate hosts) in the pond is the best prevention and treatment method.
Use relevant deworming drugs.
3. Prevention and treatment methods for intestinal disease caused by myxosporeans
Soak rice bran or wheat bran in 80% dichlorvos at 10 ppm and feed it, for 3 consecutive days.
For every 10,000 fingerlings or every 100 kg of feeding fish, mix 75 g of sulfur powder into the bait and feed it once a day, for 5-8 consecutive days.
Use relevant deworming drugs.
4. Prevention and treatment methods for intestinal disease caused by head-groove tapeworms
Feed medicated bait with trichlorfon. Mix 50 g of 90% trichlorfon crystals with 500 g of flour and feed for 3-6 consecutive days. Stop feeding for 1 day before administering the drug.
Mix 20 g of bithionol into 5 kg of rice bran, for one feeding of 100 kg of fish, once a day, for 4 consecutive days.
Feed medicated bait with pumpkin seeds. Grind 250 g of pumpkin seeds into powder, then mix evenly with 500 g of flour and 500 g of rice bran, and feed continuously for 3 days.
Grind 200-400 g of areca nut into powder, mix into the feed to make pellets, and use for 100 kg of fish once a day, for 4 consecutive days.
Use relevant deworming drugs.