How to Treat High Ammonia Levels in Aquariums

Ammonia is a toxic byproduct of fish metabolism and the decay of organic material in an aquarium. High concentrations of ammonia are inevitable in fish tanks, but beneficial bacteria can metabolize ammonia and convert it into less-harmful byproducts; promoting the growth of these bacteria is essential to having a healthy aquarium. Regular water changes and tank maintenance can reduce or eliminate any additional spikes in ammonia concentration caused by unforeseen factors, such as fish death.

Things You'll Need

  • Gravel or sand substrate
  • Rocks
  • Sinking logs
  • Biological filter (sponge filter or filter with bio-ball medium)
  • Thermometer
  • Water testing kit
  • pH balancing chemicals
  • Live plants
  • Fish net or skimmer
  • Ammonia-neutralizing chemicals
  • Buckets
  • Siphon tube
  • Magnetic algae scraper
  • Plain bleach
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Instructions

  1. Equipping Aquariums to Control Ammonia Levels

    • 1

      Use an appropriate gravel or sand substrate for your aquarium -- the increased surface area provides more room for beneficial bacteria to grow. Include sinking logs, rocks and ornaments to provide additional surface area.

    • 2

      Use a filter with a biological medium -- such as a sponge filter or a bio-ball cartridge -- to promote the growth of bacteria. Set up the filter so that the outflow water agitates the surface to provide additional water aeration.

    • 3

      Use a thermometer to monitor the aquarium's temperature. Keep the water temperature as low as the fish can thrive in -- higher temperatures increase ammonia toxicity. Float a sealed bag of ice in the water to reduce temperatures and remove the bag when the ice has melted -- never pour ice or cold water directly into an aquarium.

    • 4

      Use a water testing kit to monitor the aquarium's pH levels -- higher pH levels increase ammonia toxicity. Use pH adjusting chemicals to maintain as low a pH as the fish can thrive in.

    • 5

      Include appropriate live plants to improve water quality and provide additional surface area for bacteria.

    Avoiding High Ammonia Levels

    • 6

      Avoid aquariums that are taller than they are wide regardless of their total water volume -- the surface is where oxygen exchange occurs and where harmful pollutants are vented.

    • 7

      Avoid overcrowding an aquarium -- small fish need at least 1 gal. of water for every 1 inch of fish and larger fish need at least 3 gal. of water for every 1 inch of fish.

    • 8

      Feed active feeders only as much food as they consume in five minutes and feed scavengers and bottom dwelling fish only as much as they consume in 30 minutes. Remove any excess food with a fish net or skimmer.

    • 9

      Remove any dead plant matter or fish as soon as you notice them, including unconsumed live foods, such as mosquito larvae.

    • 10

      Use a water-testing kit every several days to monitor ammonia levels -- there will ideally be no detectable ammonia. Use an ammonia-neutralizing chemical to reduce concentrations in an emergency.

    Water Changes

    • 11

      Store the equivalent of 20 percent to 30 percent of the aquarium's water volume in open buckets at least one day prior to a water change to allow chlorine to dissipate.

    • 12

      Use a siphon tube to vacuum the substrate. Use a magnetic algae scraper to remove excessive algae growth from the glass.

    • 13

      Clean rocks or ornaments by placing them in a mixture of 1 tbsp. of plain bleach and 1 gal. of water. Allow the object to soak for at least 10 minutes, then rinse it in water until no trace of bleach odor is detected.

    • 14

      Remove 20 percent to 30 percent of the aquarium's water and replace it with the dechlorinated water. Wait one hour, then test the water's ammonia levels, nitrite levels and pH. Use water adjustment chemicals as necessary to balance the water quality.

    • 15

      Change the water every two weeks.