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SESK: Stuff Everyone Should Know · sesk.info/fish-ich-white-spots

Your fish has tiny white dots like grains of salt on its fins. What is a likely cause?

Ich is a likely cause, but white spots alone do not confirm it.

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  1. Too much aquarium light
  2. Normal new scales growing
  3. Ich, a skin parasite ✔

Why: UF/IFAS says ich lesions can look like white dots, blisters or salt grains. Other diseases can look similar, so white spots alone should not be used as the only diagnosis.

Huh, didn't know that: UF/IFAS says examining a gill or skin sample under a microscope can confirm the cause.

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What kind of fish chases mice? A catfish.
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References

Answer: Ich, a skin parasite. UF/IFAS says ich lesions can look like white dots, blisters or salt grains. Other diseases can look similar, so white spots alone should not be used as the only diagnosis.

  1. UF/IFAS EDIS: Ichthyophthirius multifiliis (White Spot) Infections in Fish ask.ifas.ufl.edu/publication/FA006
    These lesions look like small white dots, blisters, or salt grains on the skin or fins of the fish.
    Checked 2026-10-11.
  2. UF/IFAS EDIS: Ichthyophthirius multifiliis (White Spot) Infections in Fish ask.ifas.ufl.edu/publication/FA006
    White spots should never be used as the only means of diagnosis
    Checked 2026-10-11.
  3. UF/IFAS EDIS: Ichthyophthirius multifiliis (White Spot) Infections in Fish ask.ifas.ufl.edu/publication/FA006
    Gill and skin biopsies should be collected and examined with a light microscope
    Checked 2026-10-11.

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