网箱养鱼放养密度大,水环境复杂,与池养相比,鱼病防治体外用药难度大。一旦发生恶性流行性鱼病,更是很难控制。大剂量用药,集中清洗,其效果也不理想。效果不理想的原因主要有以下几点:1、网箱水体流动性大。高浓度用药虽可把鱼体表病原体杀死,但水中病原体并未根本消除,鱼体还 Cage stocking density, water environment is complex, compared with the ponds, fish disease prevention and treatment in vitro medication difficult. In the event of a pandemic fish disease, it is more difficult to control. Large doses of medication, focus on cleaning, the effect is not satisfactory. The main reasons for the unsatisfactory results are as follows: 1, Cages water mobility. Although high concentrations of drugs can kill fish surface pathogens, but the water pathogen has not been eliminated, the fish also