草鱼细菌性肠炎病在草鱼养殖中发病普遍,流行广,危害大,死亡率高,有时死亡率在60～80%以上。病鱼体表组织有黑色素沉着,鱼体呈灰黑色。行动缓慢,离群独游,时游时停,失去食欲。病鱼腹部出现红斑,肛门红肿,轻压鱼腹,有血黄色粘液流出,严重时,头一经向上提起,肛门就有粘液外流。这些粘液是肠壁充血后和肠粘膜上皮细胞溃烂而脱落下来的。此病发生与蔓延,同饲养管理有密切关系,致病原因大致有以下几点:1、养鱼较久的鱼池长久不清塘,或清塘消毒不彻底,塘内的病菌繁殖滋生,乘机侵入鱼体。2、此病易通过被病菌污染的水体、饲料、工具,以及带菌鱼种等传播,使病情蔓延扩大.3、在草鱼时饥时饱或饲料不适口的情况下,鱼的抗病能力减弱,如肠管受伤,更容易使病菌侵袭而发病. Grass carp bacterial enteritis disease prevalence in grass carp widespread, widespread epidemic, endangering large, high mortality, sometimes more than 60 to 80% mortality. Diseased fish body tissue melanin calm, gray-black fish. Slow action, outing alone, when traveling stop, loss of appetite. Diseased fish appear erythema in the abdomen, anal swelling, light pressure on the belly, blood yellow mucus outflow, serious, the first one up to the anus there mucus outflow. These mucus is intestinal wall congestion and intestinal epithelial cells ulceration and fall off. The occurrence and spread of the disease, closely related to feeding and management, the causes of the disease are generally the following: 1, fish ponds for a long time not clear ponds, or clear pond disinfection is not thorough, the breeding of bacteria in ponds, took the opportunity to invade Fish body. 2, the disease easily spread through the body of water contaminated by water, feed, tools, and fish species such as spread, so that the spread of the disease expanded .3, when the grass carp full hunger or feed unpleasant circumstances, the fish’s disease resistance weakened , Such as bowel injury, more susceptible to pathogens and invasion.