A lack of electrolytes in aquarium freshwater may cause serious health problems for freshwater fish. Aquarium Salt supplies electrolytes to improve fish respiration. Made from evaporated sea water and containing natural active ingredients such as a natural fish tonic, Aquarium Salt promotes the overall health of your fish by improving their gill function and reducing stress in a freshwater aquarium. This all-natural salt provides the essential electrolytes fish need for the uptake of oxygen and release of carbon dioxide and ammonia through the gills. Aquarium Salt should only be added to reduce stress during new freshwater aquarium setup and water changes or to promote disease recovery when solving specific fish health issues. Use Aquarium Salt when setting up a new freshwater aquarium, when changing water or treating disease. Make sure to take extra care when using salt with live plants, as some plants may be sensitive.