How to Keep Your Aquarium Cool

Why is hot weather bad for aquariums?
Water holds heat well and aquarium equipment, such as lighting, produces lots of warmth which can push the water temperature up to dangerous levels. Fish, corals, bacteria and other organisms have maximum temperatures that they are able to tolerate, and they can suffer, or die, if these are exceeded. Corals are at particular risk and may bleach - expelling their essential zooxanthellae into the water.

The high temperatures increase metabolism so fish (and other organisms, including filter bacteria) need to breathe more rapidly and have a higher oxygen requirement than they do than when the water is cooler. Unfortunately, warm water also holds less oxygen than cooler water, so the hotter it gets the more risky it becomes for your aquarium livestock.