Prevention and treatment of comprehensive complications of red and swollen grass carp

We usually refer to the occurrence of rotten Gill, enteritis and red skin disease of grass carp as "comprehensive complications of grass carp". With the improvement of the level of intensive culture, especially the use of pellet feed, this disease occurs frequently. A farmer groped for the following prevention and treatment methods for reference.

Grass carp culture

First, symptoms: grass carp is sick, the flow is slow, the body color is black, does not feed, and travels alone; the Gill filaments are red and swollen, stick with dirt, the ends rot, reveal softness, the inner epidermis of the Gill cover is congested, inflamed, and seriously corroded, showing a "skylight". The anus is red and swollen. Open the fish body, you can see mesenteric bleeding, intestinal wall inflammation, serious, purplish red, basically no food in the intestine, yellow sticky material with blood; a small amount of grass carp with decay around the anus; liver and spleen slightly swollen, liver yellowish, a little bleeding, crisp and fragile. At the time of death, half of the fish emerged from the water at an angle of 45 degrees and slanted onto the slope of the pond.

2. Epidemic situation:

It mainly harms one-year-old grass carp, with a mortality rate of about 50%. In severe cases, it can reach more than 85%. The popular water temperature is above 18 ℃, and the peak water temperature is 25 ℃.

Third, the cause of occurrence:

From January to June, Rain Water is less, and the water level of many fish ponds is only half or less than half, resulting in high relative density of fish, limited activity space, early pond water is often muddy, there is no good environment.

2. in the early stage, it was mainly forage, and a large amount of ryegrass was planted on the ridge of the pond or other places. The temperature rebounded after 3 months, and the fish had a large food intake and fast growth after a winter. Many fish farmers saw this situation and blindly fed. There were forage in the pond 24 hours a day, excessive intake of coarse forage, resulting in intestinal mucosal damage, intestinal congestion, and anal redness.

3. With the increase of temperature, a large number of grass carp feces deposited at the bottom of the pool, which exceeded the self-purification load of the water body, the water quality deteriorated seriously, the water color was thick black, and there were a lot of foam at the bottom of the pool, which created favorable conditions for rotifer and bacterial reproduction and increased the mortality rate of grass carp. Accelerate the death rate of grass carp.

Fourth, prevention and control methods:

1. Prevention: ① injects more new water at the beginning of spring, the water level is more than half, regulate the water quality regularly and improve the water environment. ② regularly checks for parasites such as rotifers to completely cut off and stop the spread of parasites. According to the four principles of ③, it is appropriate to eat about 3.5 of the forage. ④ regularly take liver-protecting and gallbladder-expanding fishery drugs to avoid bacterial diseases such as enteritis. ⑤ regularly sprinkles disinfectants to disinfect and sterilize the water body, following the principle of "prevention without disease, early treatment of disease, prevention is more important than treatment, and prescribe the right medicine to the case".

2, treatment: ① reduce the amount of food, feed as little as possible, cooperate with other feed, wait for the fish disease to improve and then slowly increase the amount. ② regularly examined the Gill of grass carp for rotifer. If so, medicine can be used to kill. Check again after two days to see if it has been killed. If there are still a small amount of rotifers, use it once after three days. At the same time take internal medicine, it is recommended to use: enrofloxacin + Vc+ stress Ning (liver protection and gallbladder expansion drugs). ③, pay attention to water disinfection. Especially when the Gill of grass carp is red and swollen and bifurcated, chlorine dioxide or dibromohydantoin should be applied in time and spread evenly throughout the pond. ④ should pay attention to the regulation of water quality and should not apply fertilizer at will, especially in fish ponds that have just stopped dying, and then wait 7 days before applying fertilizer.