The purpose of this project is to develop an effective inactivated vaccine against grouper iridovirus to control this disease. Two types of vaccine will be developed: one is combination of adjuvant and inactivated virus for injection route; the other is inactivated virus encapsulated by microparticles for oral route. The effectiveness of the vaccine will be evaluated under the experimental condition by measuring the ELISA titer of tested fish and challenging tested fish with grouper iridovirus. In addition, the propriate time for the primary immunization in grouper larvae and combination of oral and parenteral route for administration will be investigated.