SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/fish-sick-fish-separate-tank

One fish in your tank looks sick. Where does Merck say it can be watched and treated more easily?

In a separate quarantine tank, often called a hospital tank.

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  1. In the main tank with everyone else
  2. In a separate quarantine tank ✔
  3. In a cup on a sunny windowsill

Why: Merck says a quarantine tank can hold new fish or fish showing signs of disease. Moving the sick fish out makes it easier to watch and treat, and helps keep disease away from the other fish.

Huh, didn't know that: Merck says a quarantine setup should be completely taken apart and disinfected between uses.

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What do you call a fish that won't stop talking? A big mouth bass.
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References

Answer: In a separate quarantine tank. Merck says a quarantine tank can hold new fish or fish showing signs of disease. Moving the sick fish out makes it easier to watch and treat, and helps keep disease away from the other fish.

  1. Merck Veterinary Manual: Routine Health Care of Fish www.merckvetmanual.com/all-other-pets/fish/routine-health-care-of-fish
    A quarantine tank can be set up for new fish or for those showing signs of disease.
    Checked 2026-10-11.
  2. Merck Veterinary Manual: Routine Health Care of Fish www.merckvetmanual.com/all-other-pets/fish/routine-health-care-of-fish
    Isolating the fish in question also allows easier observation and treatment.
    Checked 2026-10-11.

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