淡水鱼和河蟹病害发生既有相似之处,也有明显不同。相似之处是外部环境水质腐败恶化,高温时期各类有害菌大量繁殖,鱼蟹抗病力下降。病害发生的不同之处是鱼类投喂人工商品饲料,大多数养殖生长期由过去的三年缩减为二年,成鱼由二年缩减为一年,生长速度要比以前的养殖鱼类约快三倍,鱼的机体发生明显的病理变化,肝脏、胆囊肿大,血管脆弱易出血,鱼骨变软、弯曲,养殖 Freshwater fish and crab disease have both similarities, but also significantly different. The similarities are the deterioration of the external environment, water quality and corruption, high temperature during the harmful bacteria multiply in large quantities, fish and crabs decreased resistance. The difference between the diseases is that the fish are fed artificial feedstuffs. Most of the farming and breeding periods have been reduced from the past three years to two years. The adult fish have been reduced from two years to one year and grow faster than the previous breeding fish Three times faster, significant changes in the pathological changes of the fish body, liver, gallbladder enlargement, blood vessels vulnerable to bleeding, fish bones become soft, curved, breeding