I am not the OP,,but the responder to this--calling for a flag,,,is WRONG!! You INDEED add salt to a FRESH WATER tank,,,not as much as needed for Marine Fish but Aquarium Salt is needed to replenish vital electrolytes that the fish need under stress from aggression,water changes etc,,, Whether someone is posting 100 X a day is one thing but to call for a FLAG and also give out FALSE info is equally wrong and dangerous to those with their own tanks! DO RESEARCH before you make a statement like that!!! http://www.bestfish.com/fwsalt.html it's NOT ok to contact this poster with services or other commercial interests PostingID: 1008268916 mass