Cooling a hot tank

Question
Hi Karen!
Can I cool a 20 gallon tropical tank by floating a bag of ice cubes
in it for a while?

The airconditioning is broken (very sad) and the house is a
sauna (quite revolting).  The tank is getting up to 85 - 90
degrees during the day and dropping back to about 78 degrees
overnight.

That sounds not so good...any ideas?

Airconditioning back on in a week and a half, if we are not all
turned into puddles by then.

Very Warm regards,
Gillian (Australia)

Answer
Hi there, Gillian!
Well, most fish can probably adapt and withstand higher temperatures just for a short period. Increasing aeration during this period is essential. Make sure your filter is running adaquately, add an airstone if you can. If you are very worried and your fish show signs of stress you can try running fans on the aquarium if you can. But otherwise, if your fish don't seem stressed in any way, they can most likely be able to stand high temperatures and I reckon they will be just fine until your aircondtioning is fixed.

I'm afraid floating a bag of ice would cool down the aquarium too quickly and will make your fish ill. You know how quickly 1 or 2 ice cubes will cool down a glass of water in just a few seconds??? This could be the affect your aquarium recieves when you try this. Down here in texas where I'm located, we get such hot summers that I often don't run heaters during summertime. Common ranges include usual highs of 100's F during daytime. Even our winter here has been mild with only occasional cold bouts, I guess I'm lucky for that anyway. ;-)

Best wishes to you. I am certain your fish will be fine, but if they seems stressed, you may need to give them a water change of 20-30% with water that is a few degrees (but not by many) lower than that of the aquarium which should help them. Increase the aeration because as you may know, higher temperatures lower the oxygen content of your water.

I hope this helps! Hang in there Gillian! I know how hot weather can be with no A/C can be!

Happy fishkeeping!
Karen~