水霉病俗称白毛病，是一种不易防治的鱼类常见病。水温低于２０℃时感染率最高，对受精卵的孵化和冬放鱼种的危害最大，每年死于该病鱼种达２０％左右。药剂：老姜５００克切碎磨浆，用纱布滤出姜汁，再将渣加点水再磨，又滤出姜汁，如此重复四次，姜汁总量不超过４０００克， Water mildew disease commonly known as white hair, is a common disease of fish is not easy to control. When the water temperature is lower than 20 ℃, the infection rate is the highest, the hatching of the fertilized eggs and the winter fish species are the most harmful. Each year, about 20% of the fish died of the disease. Pharmacy: 500 grams of ginger chopped refining, ginger with gauze filter out, and then add a little slag and then grinding water, but also filter out ginger, so repeated four times, the total amount of ginger is not more than 4000 grams,