API AQUARIUM SALT promotes the overall health of your fish by improving gill function and reducing stress in a freshwater aquarium. API AQUARIUM SALT should only be added to reduce stress during new freshwater aquarium setup, water changes or to promote disease recovery when solving specific fish health issues. Use 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.