King grouper (Epinephelus lanceolatus) is an important cultured marine species inTaiwan. Low survival rate was found because of susceptibility in virus-like disease fromnursery stage. In addition, their commercial value was lost in occurrence of 『headpigment losing syndrome』by rearing them with the flow-through clear seawater. Thisstudy aims to increase the survival of juvenile by the ways of prophylactic andtherapeutic methods. In prophylactic method are including of harvesting the fry beforecannibalistic stage, shorten the grading interval and supply of vitamin mixture or glucanto Artemia and trash fishes. In therapeutic method, to improve the survival rate ofjuvenile by rearing them in different environmental conditions (difference in salinity,green water or clear water, supplement of dissolved organic matter and treat withtherapeutic agent or not). The fry are planned to rear in varying water qualityconditions by different treatment methods in order to realize the occurrence of headpigment losing syndrome. The solving method will be suggested after analysis of waterquality. The profits of aqua-farmers will be improved after carrying out of this studyafter improving the survival rate of king grouper at nursery stage.