Fish-Pond-Aquarium Owners



In the fall of 2015 the City of Eden will embark on a modification of their current water treatment process. The new process will involve switching the disinfectant from free chlorine to chloramines to comply with new federal regulatory standards.

What are chloramines?

Chloramines are a disinfectant used to treat drinking water. They are formed by mixing chlorine with ammonia at carefully controlled levels. Similar to chlorine, chloramines are effective at killing harmful bacteria and other germs.

Why are chloramines toxic to fish, reptiles, and amphibians?

Chloramines are a combination of chlorine and ammonia, both of which are harmful for fish, amphibians, and reptiles. When water that contains chloramines are digested by humans that water is neutralized by the digestive system before it reaches the bloodstream. Since chloramines enter directly into the bloodstream through the gills this inhibits the red blood cells ability to carry oxygen.

Will letting the water sit for a few days cause the chloramines to disappear?

No. Unlike chlorine which will eventually dissipate, chloramines may take weeks to disappear.

What tests will determine if the water is safe for aquatic animals?

Aquaium owners should monitor their ammonia and “total” chlorine not “free” chlorine concentration levels closely. A total chlorine test or combined chlorine test should be available at the local pet or pool supply stores and chemical supply houses.

What precautions should fish shops, hobbyists and aquaculture businesses take?

Chloramines must be neutralized or removed from the water that is used in fish tanks, ponds, and aquariums. Unlike free chlorine, chloramines do not dissipate as quickly from water. As chloramines are removed, ammonia is released and must also be removed prior to coming in contact with fish, amphibians and reptiles. Households, fish shops, hobbyists and other business that keep aquatic animals should contact knowledgeable suppliers and/or veterinarians.

Are chloramines toxic to both saltwater and freshwater fish?

Yes. Chloramines are not only toxic to both saltwater and freshwater fish, but reptiles, turtles and amphibians.

Will chloramines change the pH of the water?

No. The pH of the water should remain about the same.

Will chloramines harm any other pets?          

No. Chloramines are only potentially harmful to fish and other aquatic life.

Will chloramines affect swimming pools?

No. Pool owners will still need a free chlorine residual to retard algae and bacteria growth.

Will reverse osmosis remove chloramines?

No. Only salts are caught by the permeable membranes, allowing chloramines to easily pass through.