春季,就长江中下游地区而言,指阳历3、4、5月份,3月份水温10℃以下时,各种水生生物包括细菌,尚未进入繁殖盛期,鱼池中致病菌数量少,毒力低,所以一般不会出现暴发性鱼病的大流行;4月上旬至中旬水温逐渐上升,鱼池中各种生物生长、繁殖速度加快,代谢废物不断增加,水质开始恶 In spring, in the middle and lower reaches of the Yangtze River, referring to the solar calendar in March, April and May, when the water temperature in March is below 10 ℃, all kinds of aquatic organisms including bacteria have not yet entered the breeding season, the number of pathogenic bacteria in fish ponds is low, Low, so generally no outbreak of outbreaks of fish disease pandemic; early April to mid-temperature water temperature gradually increased, a variety of fish pond life growth, breeding faster, increasing metabolic waste, water began to evil