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SESK: Stuff Everyone Should Know · sesk.info/fish-ammonia-damages-gills

What does even a low level of ammonia do to fish over time?

It stresses them and damages their gills.

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  1. Slows growth without damaging tissue
  2. Stresses them and damages gills ✔
  3. Improves resistance to bacterial infection

Why: UF/IFAS says low levels of ammonia cause stress and damage gills and other tissues. Fish exposed over time get more bacterial infections and grow poorly.

Huh, didn't know that: UF/IFAS says to test water immediately whenever a fish's appearance or behavior changes.

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References

Answer: Stresses them and damages gills. UF/IFAS says low levels of ammonia cause stress and damage gills and other tissues. Fish exposed over time get more bacterial infections and grow poorly.

  1. UF/IFAS EDIS FA031: Ammonia in Aquatic Systems ask.ifas.ufl.edu/publication/FA031
    At low concentrations, ammonia causes stress and damages gills and other tissues.
    Checked 2026-10-11.
  2. UF/IFAS EDIS FA031: Ammonia in Aquatic Systems ask.ifas.ufl.edu/publication/FA031
    Fish exposed to low levels of ammonia over time are more susceptible to bacterial infections
    Checked 2026-10-11.
  3. UF/IFAS EDIS FA031: Ammonia in Aquatic Systems ask.ifas.ufl.edu/publication/FA031
    ammonia should also be tested immediately any time fish appearance or behavior changes
    Checked 2026-10-11.

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