API Aquarium SaltAPI AQUARIUM SALT is made from evaporated sea salt and is a must have for your aquarium! AQUARIUM SALT promotes fish health by improving gill function, making it easier for fish to breathe. It also provides essential electrolytes that fish need to reach peak coloration and vitality. These electrolytes may be lost each time you perform a partial water change, and will need to be replenished. Use API AQUARIUM SALT in freshwater aquarium tanks when