养鱼生产中,要能有效地防治鱼病,首先要能正确地诊断鱼病。有些鱼病是可以肉眼直接诊断的。没有显微镜及病理检查条件的养鱼场或养鱼户,采取肉眼诊断,有一定实际意义。肉眼诊断的方法是捞取3～5尾病鱼或因病刚死的鱼,肉眼检查体表、鳃及肠管,根据明显的症状或寄生虫,作出诊断。 Fish production, to be able to effectively prevent and treat fish diseases, we must first be able to correctly diagnose fish diseases. Some fish diseases can be directly diagnosed with the naked eye. No microscope and pathological conditions of fish farms or fish farmers, the visual diagnosis, a certain practical significance. The method for the naked eye diagnosis is to fetch 3 to 5 dead fish or fish whose illness has just died, and to visually check the surface, gills and intestine, and make a diagnosis based on obvious symptoms or parasites.