1, fish inspection. Physical examination of fish is the most important and direct method to diagnose fish diseases. Inspection methods mainly include visual inspection (visual inspection) and microscopic inspection (microscope, magnifying glass, dissecting mirror). Only the visual method is introduced here. First of all, check whether there is any damage on the body surface, whether there is any change in body color, and whether there is any redness and swelling in the anus. Secondly, check whether the gill cover is open, whether the gill color is normal, whether there is a lot of mucus, and whether the gill filaments are swollen and rotten. Finally, check whether there are ascites and visible parasites in the internal organs, whether the appearance is normal, whether there are parasites in the intestine, and whether the intestinal wall is congested and inflamed.
2. Field investigation:
(1) Investigate the feeding and management of fish. Including pond cleaning methods, fish species, sources, breeding density and disinfection before stocking. Type, quantity and quality of bait; Types, quantity and quality of fertilization. If the fish pond is not completely cleared by drugs, the fish disease that occurred last year may occur again this year. Fish are prone to enteritis if they are fed with deteriorated feed.
(2) Investigate the environmental factors of fish ponds. Understand whether there are pollutants in the water source, the change of water quality and temperature, the use of pesticides in farmland around the fish pond, the quality and permeability of the bottom of the fish pond, the size and depth of the fish pond, and whether there are some fish parasites as intermediate hosts and enemies in the fish pond. If there is pollution source in the water source, it may lead to fish poisoning and death. If the water leaks, the fish will suffer from horse racing.
(3) Investigate the incidence of fish and take control measures. When did the disease begin, whether it was the same fish or multiple fish in the same pond, the number of mantis that died every day, and the treatment methods used for them.
To sum up, only a comprehensive and systematic investigation of fish body, fish feed, fish living environment and incidence can make a correct diagnosis of fish diseases in time. I believe that through the above diagnosis methods, you will soon find out the cause of fish illness.