How to Lower the Ammonia in a Freshwater Aquarium

High ammonia levels should be a red flag in your freshwater aquarium. If your test strips show that any ammonia is present in an established aquarium, it's too much. Don't hesitate to start balancing things out right away, because high ammonia can hurt your fishes' scales and other tissues, stress your fish out, decrease your fishes' appetites or even cause death.

Things You'll Need

  • Biological filter
  • Ammonia removal product
  • Ammonia test strips
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Instructions

    • 1

      Change 25 to 50 percent of your aquarium's water. Use a vacuum to remove fish waste and uneaten food from where it lurks on the bottom of your tank. Although a water change won't completely fix an ammonia problem, it will relieve some of your fishes' stress.

    • 2

      Reduce the amount of food or frequency of feeding in your tank. Fish don't need much food to thrive. Also, fish won't eat much anyway if there are high levels of ammonia in the tank, leaving all of that uneaten food to aggravate the ammonia problem.

    • 3

      Check that your filter is working. If you can, upgrade to a larger or higher-quality filter. A better filter doesn't exempt you from performing regular water changes, but it will help regulate your aquarium's nitrogen cycle. Clean your filter regularly to avoid clogging.

    • 4

      Set up a biofilter for your aquarium. Biological filters, after they've been running for six to eight weeks, contain bacteria that help regulate your tank's nitrogen cycle.

    • 5

      Don't overstock your aquarium with fish. Typically, a freshwater aquarium can support one inch of fish per gallon of water -- although it's always better to provide your fish with the largest tank you can afford. Additionally, don't add new fish to your tank if ammonia levels are high, because this will only increase the ammonia.

    • 6

      Remove dead fish and decayed or dying plants from your aquarium immediately. Quarantine any sick fish, especially if you need to treat them with medicine. Fish antibiotics can kill the ammonia-fighting bacteria in your aquarium, which will keep your fish from healing and increase ammonia levels.