CATDOLL : CATDOLL: What is the reason for the death of channel catfish and yellow catfish for several consecutive years?

In recent years, the forktail tuna, yellow sang, and river grouper in Meishan and Leshan areas of Sichuan have died every year after the spring. For example, one family lost 80,000 kilograms of forktail tuna. However, Mr. Zou, who I visited last time in Zhongxiang Town, is just the tip of the iceberg. Obviously, in addition to the customer groups we serve, there are still a large number of farmers who may have many problems in medication, correct diagnosis, and prevention, which ultimately lead to very serious losses. Next, I will share with you some of my successful experiences in treating fish deaths after the spring.

1. It is not advisable to stop feeding fish with short intestines in winter, but feeding too much is also a problem. How to correctly control the feeding degree is a technical job. As we all know, fish are active animals. Changes in water temperature affect changes in fish body temperature, and changes in body temperature naturally affect the activity of digestive enzymes in the fish intestines. The lower the water temperature, the lower the activity of digestive enzymes in the intestines, and the less feed you should give.

Everyone knows that if you eat too much delicious food, you will have stomach pain and bloating. You should take some stomach-strengthening and digestion-promoting tablets and yogurt immediately. What are the ingredients of these medicines? It is to supplement the digestive enzymes that promote digestion artificially. Its main ingredient is lactic acid bacteria. Lactobacillus can play the role of stomach-strengthening and digestion-promoting tablets and yogurt for human consumption. Protect the intestines and promote digestion. In order to prevent damage to the fish intestine caused by overfeeding, there are two ways to supplement. One is to add immune polysaccharides and liver-protecting drugs every ten days, or to regularly put them around the feed table. For small-sized fry, directly mix powdered feed with Lactobacillus casei, knead it into a ball and feed it to the pile. It has been verified that it can make the fry grow faster and stronger. Obviously, the above work is not taken seriously. We call it intestinal health care of fish. If it is not done, it is easy to have problems. Once there is a problem with the intestine, the next step will inevitably lead to a decrease in the immunity of the fish.

2. Water quality regulation. Improving the bottom quality is the key to water cultivation. To raise fish, you must first raise the water. If the pond water is not well maintained, it is another important reason for the frequent occurrence of diseases after the spring. I have some data. As long as the customer uses a lot of microbial preparations such as spore powder and enzymes, he basically does not urge me to see his fish for disease. However, farmers who usually do not pay attention to water quality regulation and only use medicine when fish die in order to save costs often urge me to see my fish for disease.

For example, the reservoir of Zhang Laoban in Suining used to produce 70,000 catties of fish a year, but there were fish deaths in the pond. Now, when it produces more than 200,000 catties a year, there are very few fish floating due to lack of oxygen. The fundamental reason is the decomposition of organic matter in the water. Fish excrement contains a large amount of undigested organic matter, and the external water source also contains a considerable amount of decaying debris. The silt layer has a large amount of such sediments deposited over the years. All these organic matter decompositions will consume a lot of oxygen, and their consumption of dissolved oxygen in the pond is far greater than that of fish.

Like many fish ponds with poor water quality, the time point when fish die in the pond is without exception when the bottom water floats up. When the biggest source of pond oxygen consumption is found and improved in advance, the self-purification ability of the fish pond water quality and the buffering capacity in bad weather will naturally increase. If there is no shortage of dissolved oxygen, then ammonia nitrogen, nitrite, hydrogen sulfide and other problems will naturally not be a problem.

3. Low immunity of fish is another factor that causes fish death. Fish immunity is closely related to the intestine, environment, feed, and health. For example, 70% of T lymphocytes and phagocytes that provide fish immunity come from the intestine, so the intestine is an important link in fish immunity. The environment is the foundation of the entire breeding, and it is also related to the level of fish immunity. In addition to the previous two links, the third factor related to immunity is feed.

Whether the nutrition of the feed is balanced, whether the storage time is too long, whether the oil is oxidized, whether the feed is moldy, whether the vitamins are lacking, these are all feed problems. Many years ago, Japan's authoritative nutrition experts pointed out that bait is the source of all diseases. In China, it was not until the day before yesterday at the science and technology conference held in Tongwei that I personally heard nutrition expert Professor Ye Yuantu frankly admit that there is a problem of excess energy in the feed, excessive addition of plant protein, and the potential risk of inducing enteritis in some fish. At the same time, due to the feeding of feed, the fish grows too fast. Whether the various organisms of the fish can adapt to the rapid growth, whether to feed immune enhancers, is also an effective means to deal with various viruses at this stage, and feed continuously for 27 days before the onset of the disease.

4. Whether the farmer stores feed properly and feeds scientifically is related to whether the fish will get sick or not. Yesterday, Mr. Liang brought his grass carp to me, and it was obvious that it had a big belly. I asked him what the feeding rate was, and he calculated that it was only 2.5%. But when the fish belly was cut open, from the front intestine to the back intestine, it was all feed, and the fullness of the food was graded from 1 to 6, it must be at level 5-6. Then I looked at the liver and saw serious fibrosis. In this case, it would be strange if the fish did not get sick and die. So why did Mr. Liang say that he only fed 2.5%, but this phenomenon occurred? It turned out that there were a large number of small crucian carp in the pond, and the feed originally used to feed the small crucian carp was all eaten by the grass carp. When the crucian carp was held in the hand, it was all in the shape of a knife. When the intestine was dissected again, there was no feed at all, only algae and organic debris. The illness and death of grass carp like this is caused by improper feeding.

5. The last cause, parasites, is the direct cause of death of forktail t and yellow mullet. Over the past year, I have found a very small parasite, only one tenth to one fiftieth the size of a red blood cell, attached to the gill filament tissue of the fish by a cilia, and a small black dot appears at the other end, constantly shaking in the adjacent area. Once the disease occurs, the gill filaments swell, the fish stop eating, crawl around, and the body surface ulcers appear. It has been found in cold water fish, cage fish, and ponds many times. It is harmful to both seedlings and adult fish. Tonight, a first-class pond fish farmer brought the fish to my house for inspection. When I checked for parasites, the amount was very large. For them, the equipment cannot see, they lack experience, and they may not be able to find it if the filming and operation are not in place. So in the past few years, they have been treating it as bacteria and viruses. There are many similar cases. In addition, this worm is resistant to many insecticides, and the diagnosis is difficult, which finally induced such a large number of dead fish.

It is very likely that the amount of food fed in the early stage was too large, which caused the water to change and caused nitrite poisoning.

1.

The amount of feed added in the early stage was too large, which caused the water quality to be unable to keep up with the regulation; it caused the water quality to deteriorate, especially the nitrite poisoning!

2.

Overeating in the early stage can cause serious metabolic system diseases, such as liver, gallbladder, and intestinal diseases. The liver of yellow bone fish will turn black, khaki and shrink, and the intestines will be inflamed, edema and congestion.

3. The fish appears thin, with protruding eyes, dull and black body color, whitish gill filaments, increased mucus, rotten gills, and serious parasitism of wheelworms on the gills.

1. The amount of feed added in the early stage caused the water quality to be unable to keep up, resulting in deterioration of water quality, especially nitrite poisoning! 2. Overeating in the early stage caused serious metabolic system diseases. Such as liver, gallbladder, and intestinal diseases. As shown in the figure below: the liver of yellow bone fish turned black, atrophied in earthy yellow, intestinal enteritis, edema with congestion and other symptoms! 3. The fish body was thin, the eyes were protruding, the body color was dark and dark, the gills were whitish, the mucus increased, the gills were rotten, and the gills were seriously parasitic by wheelworms.