1985年前,我们在预防和治疗鱼病中常年使用漂白粉这一单一药物,防治效果较差。根据笔者的调查,一般草鱼种的成活率在40%以下,草成鱼成活率在40～50%左右。我镇每年因病死的鱼约有15000公斤,占全镇鱼总产量的1O%。1985年起,我镇在2800亩精养 Before 1985, we used perennial bleaching powder as a single drug in the prevention and treatment of fish diseases, and the prevention and treatment effect was poor. According to the author’s survey, the survival rate of grass carp species is below 40%, and the survival rate of grass carp is about 40 to 50%. About 15,000 kilograms of dead fish in our town each year accounts for 10% of the total output of the town’s fish. Since 1985, my town in 2800 acres of intensive