Disease prevention and control techniques of Pelteobagrus fulvidraco

Pelteobagrus fulvidraco is a bottom economic fish widely distributed in fresh water bodies in China. While increasing the yield per unit area, increasing the stocking density and expanding the culture area, the diseases and harm of Pelteobagrus fulvidraco are also gradually increasing. Let's take a look at the prevention and control techniques of common diseases of Pelteobagrus fulvidraco.

Mechanical damage

[etiology] because Pelteobagrus fulvidraco prefers to live in groups, its pectoral and dorsal fins have hard spines, which are easy to cause mechanical damage such as skin abrasions and fin cracks in production and transportation, followed by bacterial infection and fungal infection, with rotten fins and growth water mold as the main symptoms.

[popular] mainly for cage separate culture operation and large size fish species injured after long-distance transportation.

[prevention and control] it should be operated carefully in net-pulling exercise and transportation. When emerging, the temporary cage should not be kept for too long, and the stocking density of the temporary cage should be reduced as much as possible. An appropriate amount of oxytetracycline can be added to the water for transportation, and the fish should be washed and disinfected with low concentration potassium permanganate or 30% saline solution before entering the pond or cage.

Myxosporidiosis

[symptoms] the skin tissue of the diseased fish is broken, there are irregular white spots on the body surface, and the fish body is wasting away day by day.

[control] prepare 0.1% trichlorfon solution with 90% crystal trichlorfon, soak the fish for 5 minutes, or sprinkle the whole pool with 90% crystal trichlorfon water, the dosage is 0.2 × 0.3 mg / L, once every 1 to 2 days, 3 times in a row.

Gill rot disease

[symptoms] the head of the diseased fish is black, the gills are pale with mucus, the Gill filaments rot, and the inner surface of the operculum is inflamed, congested, corroded and exfoliated.

[prevention and treatment] at the initial stage of the disease, bleach was used to hang baskets around the food farm. When seriously ill, sprinkle the whole pool with bleach solution to make the drug concentration in the pool water reach 1 mg / L, or with gallnut throughout the pool, so that the drug concentration in the pool water can reach 1 mg / L, or maple poplar leaves can be used with a dosage of 30 g / m3. Smash it and spread it all over the pool.

Hemorrhagic edema disease

[symptoms] hemorrhagic edema disease is caused by bacterial infection, the body surface of the diseased fish is yellowing, mucus is increased, the pharyngeal skin is damaged and congested with round holes, the abdomen is dilated, the anus is swollen, valgus, head congestion, swelling of the dorsal fin, congestion at the base of the pectoral and ventral fins, festering of the fins, and even longitudinal fissure of the abdomen from the pectoral fins to the ventral fins, bile extravasation. There is a large amount of blood or yellow jelly in the abdominal cavity, there is no food in the stomach, the stomach is pale, the intestine is full of yellow fluid, the liver is yellowish, the spleen is necrotic, and there are mildew black spots on the kidney. The disease is the most harmful during seedling or adult fish culture, especially in the process of seedling cultivation, with a mortality rate as high as 80%. In the hot season, the disease is easy to break out and spread rapidly.

[prevention and control] in the process of culture, we should pay close attention to the water quality, maintain good environmental conditions, keep the content of dissolved oxygen above 5 mg / L, properly reduce the stocking density of fish fry, and disinfect the water once a day after the occurrence of the disease for 3 consecutive days. When feeding fish paste, 1% salt should be added to the bait every day.

Water mildew

Symptoms: water mildew is caused by water mold infection. When the water mold was first parasitized, the abnormal shape could not be seen with the naked eye, and when it was visible to the naked eye, the hyphae had invaded the wound and grew and spread inward and outward, showing a grayish-white cotton floss attachment, and the diseased fish swam erratically and restlessly until the muscles rotted, lost their appetite and died thin. If the fish eggs were covered with hyphae, they became white velvet balls, and the moldy eggs became dead fish eggs. Serious harm to hatching eggs and young and adult fish with wounds on their body surface. The disease is most likely to occur when the water temperature is low, and it is mostly caused by improper operation in the process of pulling net, dividing boxes and transportation.

[prevention and control] in the process of fishing, transportation and stocking, the injury of fish should be avoided as far as possible and the reasonable stocking density should be mastered. Before entering the pond, the fish were disinfected with a saline solution with a concentration of 20.3%. Methylene blue was sprinkled throughout the pond to make the pond water reach a concentration of 2 mg / L, and then sprinkled again after 2 days. The fertilized eggs should be strictly disinfected before hatching, the water temperature should be controlled at 26-28 ℃, and the fertilized eggs should be sterilized again during the hatching process.