Infectious diseases are caused by plant pathogens (viruses, bacteria, molds, unicellular algae, etc.). ), divided into acute, subacute and chronic, with incubation period, aura period, attack period and recovery period. The infection forms are simple infection and mixed infection. Such as enteritis caused by bacteria, gill rot, and water mold caused by fungi. Infectious diseases invade human body through skin, mucous membrane, gills, digestive tract and excretory system, but whether they get sick or not depends on the health status of erythroculter ilishaeformis, the number of invading pathogens and environmental conditions. The scales and skin of Erythroculter ilishaeformis are effective defense organizations to prevent the invasion of infectious diseases.
Invasive diseases are caused by animal parasites (protozoa, worms, mollusk larvae, crustaceans, etc.). ), their main sources are parasitic fish and diseased fish carcasses. Contaminated feed, fishing tools, pond water, pond mud and water, plants, etc. It can also cause invasive diseases. For example, cryptosporidiosis caused by protozoa, and cucurbitaceae parasitic on the body surface and gills of fish.
In addition to the above two diseases caused by pathogens, there are many diseases caused by physical, chemical and abiotic factors. Such as "floating head" and "flooding pool" caused by hypoxia, industrial sewage, urban domestic sewage containing toxic substances and fish diseases caused by toxic substances produced by some algae blooms. This adverse effect of external conditions can directly lead to the imbalance of physiological functions of erythroculter ilishaeformis, and even lead to a large number of dead fish, which is as harmful as infectious and invasive fish diseases. For example, the water quality is too fat, bubble disease caused by oxygen saturation, frostbite caused by improper water temperature and so on.