Yellow jaw fish, "a little red disease", also known as "split head disease", "head swelling disease", is a common disease of yellow jaw fish in recent years, from fry to adult fish will be sick, water temperature 25 ~ 28 ° C incidence is more serious, so, every year from June to September is the peak period of incidence.
The disease is generally caused by "Edward's bacteria" chronic infection, when the stocking density is large, the mutually crowded stabbing injuries in the process of grabbing food, mechanical damage makes the body surface appear wounds and fish feces and excrement increase, the water quality is poor, the fish are in a semi-hypoxic state for a long time, coupled with the reduction of the activity space, the activity is weakened, or when the pond water environment is suddenly changed, such as inverted algae or water quality deterioration such as reduced pH, increased ammonia nitrogen, high nitrite, low dissolved oxygen, turbid water, etc. make Edwardian bacteria more susceptible to infection and parasitism.
The most obvious symptom of the disease is redness on the top of the scalp, and in severe cases, the skull is cracked, and a narrow ulcerated hemorrhagic band appears at the top of the head, which is a typical symptom of "split head disease", and the infection route is through the nasal infection of olfactory cells, and then enters the brain, transmening the meninges to infect the skull, forming red erosions or skull cracking symptoms. Because the infection is from the fish brain inward to the brain, so once the disease occurs, the effect of external disinfection and internal antibiotics is not good, so it is best to do a good job in advance prevention.
The main causes of the disease include the following:
1. The breeding density of fish is too large, and the frying density of yellow jaw fish is increasing, resulting in a decrease in the activity space of the stocked fish, and the mutual crowding stabbing and mechanical damage in the process of grabbing food may cause wounds on the surface of the body, making parasites, bacteria and other pathogens more susceptible to infection and parasitism.
2. There are many baits and excrement in the pond, and the water body is seriously polluted. The water quality is poor, and the ammonia nitrogen and nitrite are high. Dissolved oxygen is low, and the fish's demand for dissolved oxygen is not met for a long time, resulting in the body's growth physiological function being affected, and the physique and immunity decreasing. When the sudden change of external climatic conditions triggers sudden changes in the pond water environment such as inverted algae, turbid water, etc., resulting in the superposition of stress effects of aquatic animals, diseases are more likely to break out.
3. Lack of awareness of disease prevention, failure to regularly regulate or improve water quality and substrate, and take internally to prevent fish diseases.
The prevention of split head disease needs to pay attention to the following points in the breeding process:
1, according to their actual situation (pond conditions, water sources, etc.), choose the appropriate breeding density, the higher the pond culture density, the greater the risk of water quality regulation and disease.
2. Florfenicol is the first choice for the prevention and treatment of "split head disease", which can break through the blood-brain barrier and do a good job in the management of pond substrate and water quality. Deterioration in substrate and water quality often increases the susceptibility of farmed fish to pathogenic microorganisms. Since the yellow jaw fish is a benthic fish, it is more sensitive to changes in the substrate, and can regularly use photosynthetic bacteria, bacillus, EM for water quality regulation, and regular use of bottom modification products such as potassium bisulfate for bottom modification products for bottom improvement.
3. Regularly do a good job in the health care of fish, and regularly use immune enhancers (such as bile acids, vitamin C, etc.) to feed to enhance the physique of fish and the resistance to pathogenic microorganisms.