How to Lower the Ammonia in a Fishtank

High ammonia levels can kill fish or leave them unhealthy and vulnerable to disease. Ammonia is created in the tank as part of the natural breakdown of organic materials, like plants and fish food. Testing ammonia levels regularly is a good way to monitor the health of your tank, but fish will also exhibit health problems when levels are too high. If you see fish gasping, whirling in the tank or with abnormally colored gills, it is possible high ammonia is causing the problem.

Things You'll Need

  • Ammonia testing kit
  • Aerator
  • Small net
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Instructions

    • 1

      Stop feeding your fish, and aerate the tank vigorously.

    • 2

      Inspect the tank's filter and water for chunks of decaying organic matter. If you find any chunks, gently scoop them out with a small, fine-mesh net.

    • 3

      Change up to 50 percent of the water in the tank. Adjust the amount of water changed based on the level of ammonia present.

    • 4

      Retest the water's ammonia level. If it is close to zero, maintain the tank as usual, but feed the fish less. If it is not close to zero, go two days without feeding the fish.

    • 5

      Retest the ammonia level after two days. If the follow-up test is close to zero, start feeding the fish sparingly and maintain the tank as usual. If it is not close to zero, repeat Steps 1 to 4 until the ammonia level reaches zero.