Chlorine, Chloramine, and Fish Tanks

Fish need clean, chemically balanced water to thrive. Any time tap water is added to the aquarium, a water conditioner must be used to remove any chlorine/chloramine that is present.

Can Fish survive in Chlorinated Water?

Chlorine toxicity commonly occurs when a novice fish owner, unaware of the dangers of chemically treated faucet water, fills the tank with chlorinated tap water rather than properly aerating and treating the water. Chlorine poisoning is often fatal to fish if it is not caught, diagnosed, and treated quickly.

Chlorine kills living cells, most often damaging fish's sensitive gills as well as the skin that covers their entire bodies. Fish placed in chlorinated water will begin to suffer from respiratory problems and may suffocate, unable to breathe properly.

Preventing Chlorine Poisoning

Never use tap water in your fish tank without first treating the water with chemicals that neutralize the chlorine in the water, or by boiling it or aerating it with plenty of oxygen. If you use a chlorine-based product such as bleach to clean and disinfect anything you use in your fish tank, you need to make sure you thoroughly rinse those objects in clean water to prevent introducing chlorine into your tank. 

Aquarium test strips allow you to test your tank for chlorine, and can be purchased online or at most Pet Stores. Regular chlorine testing will help you identify problems in your tank. If your tank has too much chlorine in it, you will need to completely empty the tank and perform a full cleaning before you refill it with properly treated water. Be sure to rinse all tank accessories and equipment thoroughly before returning them to the tank.