CATDOLL : CATDOLL: What is the reason for the white spots on the gills of black fish?

1. What is the reason for the white spots on the gills of black fish?

White gill filaments may be caused by parasites or ulcers

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2. What diseases will occur in Class 1 of Black Fish?

1. Bleeding disease

【Pathogens】Various bacteria and viruses.

[Symptoms] There are hemorrhagic stripes perpendicular to the lateral line of the fish at the base of the pectoral fin and on both sides of the body wall near the posterior edge of the gill cover. When hemorrhagic symptoms appear, there will be a large number of sudden deaths within 3 to 4 days; outbreaks are prone to occur from June to September.

[Prevention and Treatment] After winter fishing, the pond must be thoroughly cleaned and disinfected with salt water before feeding bait fish; spray the whole pond with formalin to make the pond water concentration reach 20-30 ml/m3, or spray the whole pond with chlorine dioxide solution to make the pond water concentration reach 0.5 g/m3, and repeat once after 4-6 days. Oral administration of Yufukang No. 2, Yuxuesan, or Yuxuekangtai can be used, and the dosage is used according to the instructions.

2. Red skin disease

【Pathogen】Parafluorescent Bacillus.

[Symptoms] Local bleeding on the fish body surface, fish scales falling off, especially on both sides of the abdomen, fins are rotten, the fish body moves slowly, the sick fish often floats on the water surface, weak and powerless. It is often followed by Saprolegniasis and even death.

[Prevention and Control] Clean the pond thoroughly with quicklime to avoid harming the fish; disinfect with 0.5 mg/L of Xiaoling or other chlorine-containing disinfectants, such as trichloroisocyanuric acid, sodium dichloroisocyanurate, chlorine dioxide, etc.; orally take Yufukang and Yuxuekang, 250 grams per 100 kg of fish weight or use according to the instructions, mix it into the feed and feed it for 3 to 5 consecutive days.

3. Saprolegniasis

【Pathogen】Saprolegnia.

【Symptoms】It occurs at all stages of the growth of snakehead fish. It is not easy to observe in the early stage after infection. When the water temperature rises to around 18℃, it breaks out in large numbers. Blood spots appear on the fish's body surface, the fish loses appetite, and the fish loses weight. The melanin in the lesion area disappears, and the fish becomes grayish white, dull and lusterless. The fish swims alone. Finally, flocculent white filaments grow, and the muscles become turbid white until death.

[Prevention and Control] Before stocking, use 100-150 kg/mu of quicklime to clean the pond by dry method. Regularly disinfect the fish pond with quicklime or bleaching powder. During the disease period, you can also use 30-50 g/m3 of potassium permanganate to spray the whole pond. Be careful during the process of catching, transporting and handling the seedlings to prevent the fish from getting hurt, and soak them in 3%-5% salt solution for 10-20 minutes.

4. Trichodiniasis

【Pathogen】Trichodina.

【Symptoms】Mainly harms the fry and fingerling stage of snakehead fish. It can occur all year round, but is more prevalent from April to July, with a suitable temperature of 20-28℃. It is easy to get sick in small ponds, shallow water, poor water quality, insufficient bait, overcrowding, and continuous rain. The sick fish have a lot of mucus, most or all of the fish body is white, swims slowly, becomes emaciated, and dies with difficulty breathing.

[Prevention and Control] Spray the whole pond with a mixture of copper sulfate and ferrous sulfate (ratio 5:2) to make the water contain 0.7 mg/L of the drug. It can effectively kill the wheelworms on the body and gills of black carp fry and fish.

The four diseases mentioned above are the more common diseases in the process of snakehead fish breeding. Snakehead fish are aquatic animals, so the quality of water has a profound impact on the growth of snakehead fish. Therefore, during the breeding process, farmers should regularly check the pond to see if the water quality has deteriorated, change the water in time, and keep the water active, which is very important for the fish.

In the middle and late stages of snakehead fish farming, liver and gallbladder diseases often break out due to temperature changes, deteriorating water quality, and decreased resistance, causing huge economic losses to farmers.

When snakehead fish develop liver and gallbladder diseases, external manifestations are bleeding symptoms, and the most typical characteristics are hepatobiliary enlargement and discoloration. Under normal physiological conditions, the fat content in the liver is 4% to 5%. After fatty degeneration of the liver, the fat content will exceed 5%, and even reach 30% to 40%. In the early stage of the disease, the fish generally have no obvious symptoms, only loss of appetite, lack of swimming ability, etc. In the early stage, 4-5 fish die sporadically every day out of 10,000 fish. At this time, if the medication can be used in time, the condition can be easily controlled, and a large number of fish deaths in the later stage can also be avoided. As the disease progresses, the fish body color becomes black, and there is a sense of edema, swimming irregularly, losing balance or lying still in the water, slow reaction, and difficulty breathing. The autopsy liver is obviously enlarged, more than 1 times larger than the normal liver, the liver color gradually turns yellow and white, or yellow, red and white patches alternate, forming an obvious "flower liver", some livers are fragile to the touch, the gallbladder is obviously enlarged 1 to 2 times, and the bile color becomes dark green or dark green. I hope I can help you

The scales of black fish will fall off, rashes will grow on the body, causing discomfort, and indigestion will cause diarrhea and fungal infections, leading to serious consequences.

Hemorrhagic disease: When the disease occurs, bleeding stripes appear on the sides of the fish's fins and gills, and the bleeding symptoms gradually spread to the entire fish body. Red skin disease: When the disease occurs, there are local bleeding symptoms on the body surface, followed by descaling, which makes the black fish inconvenient to move and reduce its food intake. Saprolegniasis: When the disease occurs, blood spots appear on the fish's body surface, appetite decreases, and it gradually becomes thin and eventually dies. Trichodinasis: When the disease occurs, the body surface mucus increases, causing the fish's body surface to turn white, gradually becoming thin, and finally dying from difficulty breathing.

3. What are the symptoms of black fish belly turning white?

Snakehead fish, commonly known as black fish, is ferocious, has strong reproductive capacity, and has a huge appetite. It can often eat all other fish in a lake or pond, even its own young. Snakehead fish can also glide on land and migrate to other waters to find food. It can live out of water for up to three days. It is a delicacy on Chinese plates.

4. Why is the tail of the small black fish white?

It's full of bacteria. Wash it with salt water.