- This is a physiological salt based around the 4 major salts that freshwater fish need to thrive.|$|- By adding salt to a pond you relieve stress (Osmotic) on the fish.|$|- The Methylene blue in the product allows nitrite from water to be removed.|$|- Acts as a pH buffer, prevents damaging swings in pH whilst maintaining neutral stable levels for pond fish.|$|- Size:5lbs.|$|- Gender: Unisex Adult