Objectives: The objectives of this study were to identify the virucidal efficacy against the viral hemorrhagic septicemia virus (VHSV) of an aquatic disinfectant tablet composed of calcium hypochlorite. Methods: Virucidal efficacy was determined through the viability of VHSV contacted with the disinfectant in a viral stock cultured in a fathead minnow cell line. An aquatic disinfectant tablet and VHSV were reacted under distilled water (DW), hard water (HW) or organic matter suspension (OM) conditions. Results: Under DW and HW conditions, VHSV was inactivated with 24,000- and 2000-fold dilutions of the aquatic disinfectant tablet, respectively. With the investigation of the antiviral effect of the disinfectant under OM conditions, VHSV was inactivated with a 16,000-fold dilution of the aquatic disinfectant tablet. Conclusions: The results from this study showed that the aquatic disinfectant tablet was a highly effective disinfectant against VHSV. In the future, a controlled field trial is required to determine whether the use of an aquatic disinfectant tablet will be able to reduce VHSV in a cultured marine fish farm.