With dropsy that can be caused by a number of things such as a bacterial infections organ failure causing fluid buildup parasitic infection the most effective treatment I have found is a combination of maracyn2 and metroplex in food feeding a small amount twice a day for 7 days add aquarium salt 1 table spoon for 2 gallons to help reduce fluid buildup he's a recipe for maracyn2 just add one scoop of metroplex to the recipe for a more broad spectrum treatment if he isn't eating I would dose the tank with maracyn2 and metroplex