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SESK: Stuff Everyone Should Know · sesk.info/fish-starved-fish-still-makes-ammonia

If you stop feeding your fish, do they stop making ammonia?

No. Even a fish that is not eating still gives off some ammonia.

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  1. Yes, no food means no ammonia
  2. No, even a starved fish makes some ✔
  3. Yes, but only goldfish stop

Why: UF/IFAS says digesting food is the main source of ammonia, and more food means more ammonia. But even a starved fish makes some, so the filter and water changes still matter.

Huh, didn't know that: UF/IFAS says most of a fish's ammonia leaves through its gills, not its urine.

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What do you call a fish that fixes pianos? A piano tuna.
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References

Answer: No, even a starved fish makes some. UF/IFAS says digesting food is the main source of ammonia, and more food means more ammonia. But even a starved fish makes some, so the filter and water changes still matter.

  1. UF/IFAS EDIS FA031: Ammonia in Aquatic Systems edis.ifas.ufl.edu/publication/FA031
    However, even a starved fish will produce some ammonia.
    Checked 2026-10-11.
  2. UF/IFAS EDIS FA031: Ammonia in Aquatic Systems edis.ifas.ufl.edu/publication/FA031
    The more feed a fish is fed, the more ammonia the fish will produce.
    Checked 2026-10-11.

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