Seven Common Diseases of Catfish and Their Prevention and Treatment Methods

Catfish, same as sheatfish. There are many species, commonly including catfish (native catfish), big-mouth catfish, walking catfish (pond catfish), and Clarias gariepinus (Egyptian walking catfish), known as "slide brother fish" in Hakka. Catfish, kingdom Animalia - phylum Chordata - subphylum Vertebrata - class Actinopterygii - order Siluriformes - family Siluridae - genus Silurus - catfish species. They have a total of 4 barbels on the mouth, the upper ones long and the lower ones short, are carnivorous, mostly wild, have low requirements for water quality, and can be artificially farmed. They grow relatively fast, and some varieties can grow very large. Disease prevention is crucial in catfish farming, so what are the seven most common diseases of catfish? How to prevent and treat them?

The seven most common diseases of catfish are: 1 black body disease, 2 enteritis disease, 3 gas bubble disease, 4 saprolegniasis, 5 trichodiniasis, 6 tail sporozoan disease, 7 gyrodactyliasis.

Catfish black body disease

In this disease, the fish body turns black, becomes emaciated, and stops feeding; in severe cases the fish often points its head upward and hangs suspended in the surface water layer until death. Upon examination, there is a round red blood spot on the inner side of the pectoral fin, the fin rays are ulcerated, and mildew spots appear on the back of the head. This disease is easily contracted at the fry stage, and is most likely to occur when food is insufficient and water quality is poor; it develops quickly and spreads rapidly.

Prevention and treatment: keep the water clean and do not use unfermented fertilizer; splash Chinese gallnut at 2 g/cubic meter to 4 g/cubic meter over the whole pond, and splash 30 g/L quicklime water over the whole pond once every other day, 2 times to 3 times in total.

Catfish enteritis disease

The diseased fish becomes emaciated and black, with a swollen abdomen, swims alone away from the group, and when the abdomen is lightly pressed, pale yellow mucus flows out from the anus. When the abdomen is opened, abdominal fluid accumulation can be seen, and the intestinal wall is congested and inflamed, red-purple, especially in the hindgut, with the intestinal mucosa ulcerated and sloughed off. This disease is caused by bacteria or viruses, mostly occurs from July to August, and mainly harms fingerlings and adult fish.

Prevention and treatment: during the disease season, hang baskets of bleaching powder; splash bleaching powder at 1 g/cubic meter over the whole pond for 2 consecutive days.

Catfish gas bubble disease

The diseased fish floats on the water surface with its abdomen facing upward, has a gas bubble in the abdomen, and cannot sink. The cause is mainly that too much unfermented organic fertilizer has been applied to the pond, or the pond water has become aged, with too many blue-green algae in the water, causing the gas in the water to become supersaturated under strong light, and the fish ingests the bubbles by mistake.

Prevention and treatment: when the pond water transparency is too low, it is not suitable to release fry; after the disease occurs, quickly add new water and feed sufficient live bait, which can help some fry expel the bubbles and recover to normal; for every 1 m of water depth, use 1.5 kg to 2.0 kg of table salt mixed with water and splash it over the whole pond, which has a certain therapeutic effect.

Catfish saprolegniasis

After the diseased fish is infected with Saprolegnia, gray-white clumps of hyphae appear on its body surface, shaped like cotton fluff. After the hyphae gradually spread, the fish swims abnormally, skin mucus increases, appetite decreases, and finally it becomes emaciated and dies. The cause is mostly injury during capture and transport, or frostbite caused by low temperatures.

Prevention and treatment: pay attention during handling and do not injure the fish body; the water temperature of the overwintering pond should be controlled above 15°C; splash bleaching powder at 1 mg per milliliter over the whole pond; splash a mixture of 0.4‰ table salt and 0.4‰ baking soda over the whole pond.

Catfish trichodiniasis

Large Trichodina parasites on the skin and fin rays, causing the body color to turn black, the body to become emaciated, and swimming to become slow. Small Trichodina gather at the edges and gaps of the gills and keep sliding on the gills, irritating the gill tissue; in severe cases the gill filament edges turn white and rot, and the diseased fish becomes dark and emaciated, staying away from the group and swimming slowly near the pond edge. When parasitized in large numbers, the growth and development of young fish are hindered and may even lead to death.

Prevention and treatment: thoroughly clear the pond with quicklime and do not use unfermented organic fertilizer; when dividing, transferring, or overwintering fry and fingerlings, soak them in 8 mg/L copper sulfate; splash a mixture of 0.7 g/cubic meter copper sulfate and ferrous sulfate (5:2) over the whole pond.

Catfish tail sporozoan disease

Thelohanellus sinensis parasitizes the fin rays and skin of fish, causing gray-white dot-like small tumors or block-like formations on the fish body. It mainly harms fry and fingerlings cultivated in earthen ponds.

Prevention and treatment: remove excess sludge; quicklime can kill the spores in the sludge; splash crystalline trichlorfon at 0.3 g/cubic meter to 1.0 g/cubic meter over the whole pond.

Catfish gyrodactyliasis

The movement of Gyrodactylus parasitizing the fish body damages the fish's body surface and gill filaments, causing the fish body to secrete gray-white mucus; severe infection can cause death in batches. This disease mainly harms young catfish cultivated in earthen ponds and spreads through hosts or water flow. It is prevalent when the water temperature is around 20°C.

Prevention and treatment: when fingerlings enter the pond, soak them in trichlorfon at 2 g/cubic meter to 3 g/cubic meter; sprinkle 90% crystalline trichlorfon at 0.2 g/cubic meter to 0.3 g/cubic meter over the whole pond; splash a mixture of trichlorfon and sodium carbonate (ratio 5:3) at 0.10 g/cubic meter to 0.24 g/cubic meter over the whole pond.