Pondcare Pond Salt, Provides essential electrolytes fish need to survive with an all-natural salt, 4.4 lb. 156C

Provide essential electrolytes fish need to survive with an all-natural
salt, made from evaporated sea water. Improves gill function, protects
against nitrite toxicity & reduces stress by helping to maintain a
natural balance of electrolytes in the body fluids of pond fish.