How do I reduce the ammonia level in my fresh water aquarium? — Anthony, Pompano Beach, Fla.
Marshall Brain answered:
The ammonia in your tank is created by the fish swimming in the tank. When they pee and poop, they add ammonia to the tank. If you add a bunch of new fish to a tank, ammonia levels can rise. Too much food can also cause ammonia problems. Check to make sure that your filter is working and the carbon in it is fresh.
The easiest way to reduce ammonia levels quickly is to remove half of the water in the tank and replace it with new water. Make sure you treat the new water to remove chlorine and make sure the temperature of the new water is the same as the temperature or the water in the tank (or you may shock the fish with the temperature change).
If that does not help, you may wish to clean out the gravel in the tank. Remove the fish from the tank, then remove all the gravel and wash it in a colander with running water. Then put the tank back together.
You may also want to visit the local pet store with a water sample. Some pet stores will analyze your water for free and offer advice. They may notice a pH problem with your water. Or buy pH test strips, test the water yourself and balance the pH.
When you first set up a tank, the ammonia levels can rise as the bacteria in the tank are establishing themselves. This video talks about the problem:
See also this page: Ammonia Poisoning