Prevention and treatment of complications of fish fingerling

Rare complications of rotten gills, enteritis and bleeding occurred in Sanhe Town, Hongze County, Huaian City, Jiangsu Province, resulting in large-scale death of fish species. Now the specific situation of the disease and prevention and control measures are summarized as follows for everyone to discuss.

Onset time and symptoms: sporadic dead fish appeared in early August, diseased fish had rotifer on the Gill, and others did not have any symptoms. Around the middle of August, a large number of deaths occurred, and all of them were grass carp fingerness. the diseased fish were blackened and lay down, unable to float at the edge of the pond, stopped feeding, picked up the diseased fish for examination, opened the Gill cover, and after taking insecticidal measures, there were no insects, but Gill filaments rotted and adhered, and there were bleeding spots at the base of the ventral fin. After dissection, it was found that the intestines were congested and had no food, died quickly, and had no other obvious symptoms. All the sick and dead fish show three symptoms, namely, rotten gills, bleeding, and enteritis, and this syndrome is also the peak of fish death. the peak of this kind of dead fish lasts about 20 days, with 15 to 20 kilograms per mu per day. in serious cases, it reached more than 30 kg / mu, and the food intake decreased gradually in the whole process of fish disease, until some Tangkou stopped feeding at last.

The author believes that there are two reasons for the occurrence of this disease. The main results are as follows: (1) there are some problems in the methods and dosage of disease prevention and treatment. (2) the quality of water quality and the feeding of bait are the main culprits for the outbreak of fish disease.

First of all, the measures for disease prevention and treatment are not in place. As the saying goes, prevention is more important than cure. Through the investigation, the author found that the adjacent four households without disease were killed thoroughly in the early prevention and control of ring worm and rotifer, while the onset of the pond was caused by rotifer at the beginning, which caused rotten gills and then caused enteritis and bleeding. So early pest control is the key.

Secondly, because of the large amount of pellet feed, fishermen are happy to see the rapid growth of fish after eating feed, and they do not care about the feed coefficient in order to pursue high yield. the protein intake exceeds the standard, and the feeding coefficient is more than 5: 6. Not only that, the protein content fed by some farmers is as high as 32%. Grass carp has a big belly and a round waist, loses its resistance and cannot withstand any attack from the outside world. At the same time, due to continuous rain, lack of light, and the large amount of organic matter deposited by a large amount of pellet feed, the water quality worsened, and the water color of most fishing ponds was dark green, and some of them had emitted a stench. Although a large number of water changes were carried out at this time, it did not make much difference.

As a result, the author summarized the main measures to prevent complications during the fish culture period: (1) killing insects regularly and thoroughly; (2) keeping the water quality good; (3) feeding pellet feed reasonably. Treatment measures: sterilize and disinfect in time and scatter the whole pool with fish fungus poison net. At the same time, oral administration of the "four diseases of grass carp" can be observed to have an obvious improvement, and the number of dead fish has also been greatly reduced. On this basis, the control effect can be further achieved by deepening the pool water and lowering the water temperature.