Symptoms of fish poisoning

1. Symptoms of fish population poisoning increase on the water surface, ponds, reservoirs, ditches and other water surfaces in winter, fish pyrethroid pesticide poisoning is easy to occur. After fish poisoning, the population mainly floats on the water surface, drifts with the current, and the fish body is out of balance. At the beginning of poisoning, there is instantaneous excitement, then swimming slowly, slow response to surrounding stimuli, the fish lying still and lying on its side, the tail slowly swinging, the mouth slowly opening and closing, and finally sinking to the bottom of the water to die. The time from the beginning of poisoning to the appearance of death poison is short, and the mortality rate of fish poisoning is high. The symptoms of fish poisoning to different pyrethroid pesticides are slightly different. at present, the main varieties commonly used in agricultural production in the market are fenpropathrin, cypermethrin and cypermethrin. Now they are described respectively: ① cypermethrin 20% EC preparation. The crude drug is a brown liquid, insoluble in water, soluble in organic solvents, stable in neutral and acidic conditions, and easy to decompose and fail in case of alkali. The drug is a pyrethroid insecticide, which has the general characteristics of pyrethroid insecticides, broad spectrum, high efficiency, rapid, low residual toxicity and long effect. The drug kills insects by contact, stomach poison and refusing to eat. After the fish population was poisoned, it stopped swimming, floated, swam, and then stopped at the bottom. In low concentration water, fish showed symptoms of neurotoxicity, which lasted for 1 ~ 2 days, while at high concentration, fish died rapidly. Fenpropathrin is moderately toxic to humans and animals and highly toxic to fish. ② pyrethrin is a yellow oily liquid, which is soluble in xylene. Fish poisoned by permethrin have Gill congestion and can easily lead to deformities. ③ cypermethrin is yellow or brown, soluble in a variety of organic solvents, has contact, stomach toxicity and antifeedant effect, and belongs to neurotoxic insecticides. When the fish population is poisoned, they begin to show excitement, swim wildly, then lose their balance, twitch, paralyze, and are on the verge of death.

two。 The main symptoms of fish poisoning are blackening from back to tail. The body color of poisoned fish varies with different doses, the degree of blackening is different, the concentration is high, the change of body color is obvious, the concentration is low, the change of body color is small; the change of body color is also different when the poisoning time is different, when the concentration is the same, the poisoning time is long, the body color changes greatly, the exposure time is short, and the change of body color is small. After being stimulated, the poisoned individuals are extremely excited and some jump out of the water, swim aimlessly, and then drill into the water again and again, repeatedly and alternately. The eye is characterized by exophthalmos, fundus congestion or bleeding. Gill cover bleeding, Gill color light, black dirt, Gill cover, mouth open, from fish whitening to death struggle time up to 12 hours. Check the internal organs, there is no obvious swelling of the gallbladder, bile becomes thinner, the liver is punctate hyperemia, degeneration is fragile, and the liver color becomes pale as khaki.