1.秋季鱼病偏多的原因(1)养殖密度大。鱼类经过春、夏季节的生长,进入秋季个体渐渐长大,随着养殖密度上升,鱼类排泄物增加,有机质污染超过池塘自净能力时,水质会出现不稳定或变坏,导致鱼病增多。(2)水质条件差。在持续高温的秋季,养殖水体的分层现象特别严重,池底总处于缺氧状态,导致亚硝酸盐和氨态氮等有害物质浓度增加,水质调控困难,极易暴发各种鱼病。(3)投入品增多。进入夏秋季节,鱼用饲料、肥料及鱼药等投入品使用 1. The reasons for the large number of fall fish disease (1) breeding density. After the spring and summer seasons grow, the number of fish entering the autumn gradually increases. As the density of fish increases and the fish excretion increases, the organic matter pollution exceeds the self-purification capacity of the pond, and the water quality will be unstable or deteriorate, leading to an increase in fish diseases . (2) poor water quality conditions. Stratification of aquaculture water is particularly serious in the autumn with continuous high temperature. The bottom of the pond is always in the state of hypoxia, causing the concentration of harmful substances such as nitrite and ammoniacal nitrogen to increase. Water quality regulation is difficult and it is easy to outbreak of various fish diseases. (3) increase in inputs. Into summer and autumn, fish feed, fertilizers and fish drugs and other inputs used