Based on the epidemic features,etiology and pathologic characteristics of the disease,the causative agent was identified as Cryptocaryon irritans.Upon the isolation of the parasites,efforts were made to inactivate the ciliate by using several disinfectants and herbal compound.The results showed that H₂O₂ and herbal compound were both effective to kill the parasite.In clinical treatment,the combined use of “HD-2” and 100-200 mL/m³H₂O₂ was proved to control the disease effectively.The present study represents the first report to use H₂O₂ and herbal compound instead of formaldehyde for the disease treatment.The treatment established in this study is highly effective,and contains no poisonous substance,with no residues in fishery products,which provides insight into the fish disease prevention and treatment,as well as into the quality maintenance of aquatic products,with the protection of ecological environment.