When adding water to a pond, the tap water that comes from your hose contains chlorine and chloramines, which are harmful to your fish. Chlorine is toxic to most aquatic life, and it can cause stress and bad burns to the fish once it reaches the gills and its internals. Chlorine will cause burns upon contact, damaging the gills, scales, and breathing tissue of goldfish and koi. Also, interestingly, it readily enters the blood stream after it passes through the gills, causing internal burning, stress, and significant pain to the fish. The solution to this is to add the Pond Company’s Dechlor. Dechlor is short for a water dechlorinator, which is a water conditioner that neutralizes the chlorine, chloramine, and other heavy harmful substances. Dechlor should always be used whenever we add water to a pond, and whenever we do a water change to neutralize the chemicals before they affect the fish and the ecosystem. A bottle of the Pond Company’s Dechlor can be purchased for only $17.95 (see store), please give us a call if you are interested in purchasing (626)-284-5937 or drop us an email at: info@thepondcompany.com.