SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/fish-outage-hot-tank-fan

During a summer power outage, your tank gets too warm. What does a UF fish vet suggest?

Blow a battery-powered fan over the open top and cool it slowly.

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  1. Dump a bag of ice straight in
  2. Wrap the tank in a thick blanket
  3. Blow a battery fan over the open top ✔

Why: A fan over the open top cools water by evaporation. Florida Sea Grant says to cool slowly, about 1 to 2 degrees F every few hours, and to focus on aeration and evaporation rather than ice.

Huh, didn't know that: Florida Sea Grant says larger tanks stay cooler longer than small ones when the power is out.

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References

Answer: Blow a battery fan over the open top. A fan over the open top cools water by evaporation. Florida Sea Grant says to cool slowly, about 1 to 2 degrees F every few hours, and to focus on aeration and evaporation rather than ice.

  1. Florida Sea Grant: Q&A, How to Keep Your Fish Tank Safe During a Power Outage www.flseagrant.org/qa-how-to-keep-your-fish-tank-safe-during-a-power-outage
    consider blowing a battery powered fan over the open top to provide evaporative cooling.
    Checked 2026-10-11.
  2. Florida Sea Grant: Q&A, How to Keep Your Fish Tank Safe During a Power Outage www.flseagrant.org/qa-how-to-keep-your-fish-tank-safe-during-a-power-outage
    the safest way to change the temperature is gradually
    Checked 2026-10-11.

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