In late September, the autumn wind rises, the weather is slightly cooler, the temperature difference between day and night increases, the amount of chilled feeding soars, the water quality becomes poorer, and the parasitic disease of The California perch, the rotten gill disease, the ulcer disease, the Noka disease, the enteritis and other diseases are frequent (the fish pond mainly based on ice fresh feeding has more disease, and the fish pond mainly fed with feed has less disease), causing different degrees of loss to some farmers. At this stage, the disease prevention and control of California perch still adheres to the principle of "early treatment of diseases, early prevention of diseases, and prevention is more important than treatment". The common diseases and prevention and control measures of several common diseases of California perch at this stage are introduced as follows for the reference of the majority of farmers.
A common disease
1. Parasitic diseases:
At this stage, the main parasite is anchorhead bream, commonly known as "nail worm".
1. Main symptoms and hazards: Anchorhead gills are mainly parasitic on the surface, gills and mouth of fish, especially in the dorsal fin, caudal fin and fin, and the parasitic site is inflamed and red and swollen, erythema appears, and then necrosis, and the wound creates conditions for bacterial invasion. If the treatment is not timely, it will cause rotten body, Noka disease, etc., which may cause major losses, and it is necessary to pay enough attention.
2. Bacterial gill rot disease
1. Main symptoms and hazards: the sick fish is black in color, eating less or not eating, swimming edges, and slow response. On examination of the gills, gill flaps may be whitish, decayed, or with silt, and secrete large amounts of mucus. The worse the water quality, the more likely it is to cause the disease. Rotten gills can cause difficulty exhaling, loss of appetite, and emaciation in sick fish, and in severe cases can lead to a large number of deaths in California perch.
3. Bacterial hemorrhagic disease
1. Main symptoms and hazards: the diseased fish swims on the edge, the response is slow, the gills are congested, the anus is red and swollen and prominent, the caudal fin and abdominal fin are congested, and the caudal stalk is seriously congested. After the dissection, the liver is congested and the spleen is black and red. Some dead fish turn yellow after being caught. The disease is mainly caused by feeding spoiled chilled or feed and deteriorating water quality. The onset of disease is urgent, the infection is rapid, and there are many deaths.
4. Rot disease (also known as "rotten body disease", ulcer disease)
1. Symptoms: At the beginning of the disease, a number of small red spots (commonly known as "flower body") appear on the surface of the fish body, and as the disease develops, the spots gradually expand to round, oval or irregular lesions of different sizes. Scales or fins fall off at the lesion site, muscle decay, and in severe cases, bones are exposed, such as lesions on the head, and the skull is often exposed. Visceral lesions are usually not obvious. The disease is fierce, once the disease occurs, three days will cause a large number of illness and death, if not taken in time, the mortality rate is as high as 80%, the harm is serious.
5. Nocard disease
1. Symptoms and hazards: sick fish swim edge, slow response, do not eat, some ulcers on the surface of the body, some long pustules, can squeeze out white pus, tail fins sometimes ulcerated and bleeding. After dissection, there are small white or yellowish nodules on the surface of the liver, and in severe cases, white or pale yellow nodules can be clearly seen in the spleen, kidneys, muscles, and even on the gills. The high incidence of this disease is easy to cause large-scale deaths of California perch and cause significant losses to farmers. Sufficient attention is needed.
Two therapeutic measures
1. Usually do a good job in liver protection and bile protection, intestinal care, and timely reduce or stop materials when the disease occurs
After the onset of the disease, it is appropriate to reduce feeding and reduce the digestive burden of the body. A small amount of feeding can be done at the beginning of the disease, in order to add immune enhancers to the feed and improve the ability to resist diseases, it is recommended to use a continuous mixture of aoside for a course of feeding. During periods of rapid rise in deaths and peak deaths, materials must be discontinued. Practice has proved that in most cases, stopping feeding after the onset of the disease is a more effective measure to control the number of viral disease deaths.
2. High-intensity oxygenation, multi-use ecological preparations to divert water and stabilize water
High-intensity oxygenation can not only ensure oxygenation but also raise algae and water, which is conducive to stabilizing water quality and effectively reducing the stress caused by changes in water quality during the onset of the disease. After the onset of the disease, the aerator equipped capacity is recommended to reach 1.5kW/mu, which plays a real role in oxygenation, water stability and disease prevention. At the same time, fish ponds with poor water quality, turbidity and stratified fish ponds need to be regulated by water quality.
3. Disinfect with iodine preparations to prevent secondary infection
After the onset of the California perch, a large part of the fish body surface has ulcers, and proper disinfection of the water body with good quality and small irritation can prevent secondary bacterial infection and increase the amount of death. Good iodine preparations can also effectively reduce the virions in the water body, reducing the possibility of viruses transmitting each other between fish bodies.
4. Precautions for pulling nets and crossing ponds
A week before preparing to pull the net, you can feed the mixture for a week, enhance the body's immunity to resist stress, try to choose a sunny morning to cross the pond, when pulling the net, you can splash the pride in the fish collection area can effectively prevent fish stress.
5. If there is an outbreak now
Be sure to use Chinese herbal medicine treatment in time, can no longer use chemical drugs, use Ao Worm Net + Ao Ba Huang, timely exorcism of parasites, treatment of the fish due to parasite bites caused by rotten body, rotten cheeks, bleeding and other diseases, and later and with Ao Ide continuous mixing, repair the fish's liver and gallbladder.