Since your description is not very clear, I cannot make a definite judgment. I have to tell you all the knowledge about the diseases of yellow catfish so that you can know how to prevent and treat various situations in the future. Although yellow catfish has strong disease resistance, as the stocking density increases, coupled with improper management and operation, diseases often occur, resulting in a reduced survival rate. Therefore, strengthening disease prevention and control is a key measure to ensure breeding output and economic benefits. Common diseases and prevention methods of yellow catfish are introduced as follows:
1 Field fungal enteritis
1.1 Cause Caused by infection with Aeromonas punctata.
1.2 Symptoms: The abdomen of sick fish is enlarged, the anus is red and swollen, and yellow mucus flows out of the anus when the abdomen is pressed lightly. The intestines are inflamed, light red, and filled with blood and pus. Sick fish drift away from the school, move slowly, and lose appetite.
1.3 Prevention and control ① Do not feed rotten and moldy bait. Live bait should be disinfected with 2% to 3% salt before feeding. Regularly add 0.1% fresh garlic juice to the bait; ② Sprinkle the whole pond. 0.3g/m3 strong chlorine or 0.5g/m3 chlorhydantoin; ③Feed chemical bait, add oxytetracycline 0.05g per kg of bait, for 10 days; ④Feed sulfaguanidine chemical bait, every 100kg fish on the first day Take 1og of medication, and reduce the dosage by half on days 2-6.
2 Hemorrhagic edema
2.1 The cause is bacterial or viral infection.
2.2 Symptoms: The body of the diseased fish turns yellow, mucus increases, the pharyngeal skin is damaged and congested with round holes, the abdomen is enlarged, the anus is red and swollen and everted, the head is congested, the bases of the pectoral and pelvic fins are congested, and the fin rays are ulcerated ;Bile extravasation. There is a large amount of blood or yellow jelly in the abdominal cavity, no food in the gastrointestinal tract, the liver is earthy yellow, the spleen is necrotic, and the kidneys have moldy black spots.
2.3 Prevention and treatment ① Disinfect water with dibromohydantoin 0.5g/m3 for 3 days; ② Feed medicinal bait, add 0.79 tetracycline or 0.5g ciprofloxacin per kg of bait, and feed continuously for one week; ③ Increase the amount of water change and regularly use quicklime 15-20g/m3 for disinfection.
3 Saprolegniasis
3.1 Caused by water mold.
3.2 Symptoms: The sick fish swims slowly, has cotton-like attachments on the body surface, and the fish becomes emaciated and weak and dies. This disease is most likely to occur when the water temperature is low, and it is often caused by pulling the net and improper operation during transportation.
3.3 Prevention and control ① During the fishing, transportation and stocking process, operate with caution to avoid injury to the fish; ② Soak with 20g/m3 of water mold for 105 minutes; ③ Sprinkle 0.3g/m3 of water mold throughout the entire pond; ④ First, soak the diseased fish in 5% salt water for 5 minutes, and then soak it in a solution of 100kg water and 800,000 units of penicillin for 10 minutes.
4 Trichodiasis and Trichodiasis
4.1 Cause It is caused by trichozoa or trichodiasis parasitic on the gills and skin of fish in large numbers, and mainly harms yellow catfish seedlings.
4.2 Symptoms: The diseased fish are restless, floating to the upper layer and swimming wildly, or spinning on the water surface with their abdomen facing upward. Microscopic examination shows that a large number of trichozoa or schistophora are parasitic on the gill filaments and skin mucus.
4.3 Prevention and control ① Sprinkle 0.7g/m3 copper sulfate and ferrous sulfate mixture (5:2) throughout the pond; ② Sprinkle compound fish and insect net 0.3--0.4g/m3 throughout the pond; ③ Use Sprinkle 0.15g/m3 of fish and insect killer in the entire pond; ④ Use quicklime to thoroughly clean and disinfect the pond.
5 Cucurbita disease
5.1 Cause: Cucurbita disease is caused by polyspora on the skin and gill filaments of fish.
5.2 Symptoms: Small white spots are visible to the naked eye on the skin of the diseased fish. Use tweezers to remove the small white spots and place them on a glass slide. Drop a drop of water. The naked eyes can see the small white spots moving slowly in the water. Place Diagnosis can be confirmed by observation under a microscope.
5.3 Prevention and treatment ① Soak the fish body with formalin 50g/m3 for 10 minutes; ② Spray the whole pond with compound fish insecticide 0.3--0.4g/m3; ③ Use hydrochloric acid 20g/m3 Bath for 15 minutes.
6 Ringworm and third-generation ringworm
6.1 Cause It is caused by ringworm or third-generation ringworm parasitic on the gill filaments and skin.
6.2 Symptoms: The gill filaments of the diseased fish are swollen, the gills are partially pale, the fish has difficulty breathing, the fish is emaciated, swims slowly, loses appetite and dies.
6.3 Prevention and control ① Spread 90% crystalline trichlorfon 0.5g/m3 over the whole pond; ② Spray compound fish insecticide 0.4g/m3 over the whole pond; ③ Spray insecticide 0.15g/m3 over the whole pond .
7 Anchorhead worm disease
7.1 The cause is caused by the parasitism of Anchorhead worm.
7.2 Symptoms: The sick fish is restless, swims slowly, and the parasitic area is congested, inflamed, swollen, and erythematous. The parasitism of the anchorhead eel is visible to the naked eye.
7.3 Prevention and control ① Sprinkle 90% crystalline trichlorfon 0.5g/m3 over the whole pond; ② Spray fish and insect killer 0.15g/m3 over the whole pond.
In short, when dealing with yellow catfish diseases, we must adopt the policy of "prevent when there is no disease, treat when there is disease early, and prevention is more important than cure" in order to prevent or reduce losses caused by diseased fish. Pay attention to maintaining fresh water quality, and be careful in operations such as pulling nets and transporting them. Yellow catfish is a particularly lepidic fish, and its tolerance to drugs is not as good as that of the catfish, so the dosage of drugs must be accurately controlled.