GW01 and GW02 were the fusants between Nocardia sp. and Candida sp. through inter-kingdom protoplast fusion using PEG, Ca 2+ , lysozyme and snailase. After analyzing the comparisons of form, resistance to ant ibiotics, heat resistance, acid resistance and the growth rate, GW01 and GW02 could be conf irmed to be the true fusants. The fusants were more widely suitable to the fishery water quality than the parental strains. They could rapidly degrade the harmful compo sition of the water, such as COD, NH 4 , NO-2 , PO3- 4 , improve the concentration of DO and the biodiversity of the microorganisms in the water. The results suggested that the technique of inter-kingdom protoplast fusion might offer ideally new strains for bioremediation for the degeneration f ishery ecology.