冬季枯水季节,春节前群众素有干塘将鱼一网打尽而上市的习惯。其实冬季干塘库也应捕大留小,对达不到商品规格的经济鱼类,都应留做翌年饲养,这至少有四点好处: 一是生长快:家鱼的生长特性中,年龄与生长速度是一条抛物线,即500克以内的生长慢,500克以上的生长快。草鱼从5克的鱼苗长至500克和500克长至3～4公斤重所需时间基本上一样,故有“易上七八,难上一斤”的说法。二是抗病害:老口鱼种生活力强,耐受严寒、高温、缺氧等恶劣环境比小规格鱼种强得多。而且抵抗力强,发病少。如草鱼出血病危害的主要对象就是1龄的 Winter dry season, the masses known as the dry pond before the Spring Festival will catch all sorts of fish and the habit of listing. In fact, dry ponds in winter should also catch large and small, for those who reach the commodity specifications of economic fish should be kept for the following year feeding, which at least four advantages: First, the growth of fast: the growth characteristics of domestic fish, age And the growth rate is a parabola, that is, less than 500 grams of growth slow growth of more than 500 grams. Grass carp from 5 grams of fish fry up to 500 grams and 500 grams up to 3 to 4 kg weight time is essentially the same, so there is “easy on the seventy-eight, hard to pound” argument. Second, disease resistance: the old mouth fish species strong vitality, tolerance to cold, high temperature, hypoxia and other harsh environments much stronger than the small size of species. And strong resistance, less disease. As the main object of grass carp hemorrhagic disease is the first age