Prevention and treatment of rotting Gill Grass fingerling with Black head and Black back

Grass carp culture

First, the characteristics of the black head and black back of grass carp: 1. The disease occurs from April to June every year, which mainly harms the grass carp species of 150ml 400g / tail. 2. Symptoms of the disease: fish species often float and do not sink, swim, blackhead, black back, erosive Gill. Dissection showed hepatobiliary lesions and redness in part of the intestines of grass carp.

Second, the causes of the disease and the causes of difficult treatment:

The main results are as follows: (1) the cause of disease: the quality of ① grass carp needs to be improved. The unreasonable distribution of ② feeder, long-term hypoxia in feeding area and high-density culture make grass carp species more likely to be anoxic. In the early stage of ③, the content of organic matter in water was too high and the water quality was easy to deteriorate due to the feeding of all kinds of green fodder. Some grass carp species appeared Gill mold and secondary serious Gill rot. In the early stage of ④, parasites such as rotifer, ring worm and Cryptotrichum were not killed completely, and parasites were parasitized for a long time, resulting in the outbreak of erosive Gill in the later stage.

(2) the reason of difficult treatment: the treatment method of ① is not symptomatic. ② blindly chose strong stimulating drugs to accelerate the death of grass carp. ③ disease emergency disorderly medical treatment, the use of drugs, chaotic, miscellaneous, hindering the follow-up treatment work.

3. Preventive suggestions: ① should adjust the bottom and water quality of ponds fed a large amount of green fodder from March to April, and suggest using oxidized bottom modification products to prevent Gill mildew. ② reasonably arranges the feeder, paying attention to the oxygen increase and bottom change in the feeding area. After the beginning of spring, ③ should mix multi-dimensional and immune products in the feed in time to enhance the physique and immunity of grass carp. ④ should do a good job in killing rotifers and ring worms from April to May, and kill insects thoroughly. ⑤ to do a good job of routine disinfection and prevention, it is recommended to choose: compound iodine, or Xerox (mainly composed of 20% glutaraldehyde + 5% hydrocarbon amine salt) combined with thioether floxacin.

Fourth, suggested measures for treatment. ① choose insecticides for symptoms. If no obvious parasites are found, it is recommended to sprinkle Ivermectin (main ingredient Ivermectin, 6 mu per bottle, 1 meter water depth, the same below) + complexed copper (3 mu per bottle) evenly throughout the pond. ② disinfection, when the PH value of the water body is more than 8, Shiqile and fuxuedine (the main ingredient is 45% benzalkonium bromide), a set of 3 mu is used; when the PH value is less than 8, a bottle of compound iodine solution is sprinkled evenly in the whole pool. ③ sprinkles Enzanin (the main ingredient enrofloxacin) + Sanhuang Powder once a day in the feeding table. Dosage: Ensanin, Sanhuang powder one to two packets, Sanhuang powder soaked in boiling water, the effect is better. Take ④ orally, every 500kg grass carp use 1 pack of Ensanning + 2 packets of Sanhuang Powder + 1 pack of Weixian for 5-7 days. After the condition of ⑤ is stable, follow-up bottom modification and water quality regulation can be done, and oxidizing bottom modification products such as Chi Di'an can be used to improve bottom quality and water quality.