The susceptibility of turbot aquareovirus to five chemical agents was examined. Treatment with 5 mg of malachite green per liter or 500 mg of iodine per liter resulted in a 90% reduction in virus titer within 1 h. Complete inactivation within 5 min was obtained with 2% formalin, 42.5% isopropanol, or 15 mg of free available chlorine per liter. Lower concentrations of chlorine were ineffective.