Cool down the aquarium - some tricks

Most of the fish in our aquarium like it warm. However, they are still very sensitive to fluctuating temperatures and water that is too warm. Incidentally, algae growth quickly becomes a problem when the water is too warm. So you actually have to cool the water in the aquarium in summer. Here are the options that provide cooling.

Know fish - recognize danger

You should keep an overview of which temperatures the fish in your aquarium can tolerate well. Some tropical fish can even tolerate temperatures above 30 degrees, while various domestic fish desperately gasp for oxygen at a water temperature of 20 degrees.

  • Also read - Rebuilding an aquarium - Tips & Tricks
  • Also read - Cloudy water in the aquarium - 5 solutions
  • Also read - Polish out scratches on the aquarium

Donate shade

First of all, you should definitely provide shade in the warm season. An aquarium should never be in direct sunlight anyway, but especially when it is warm, every ray of sunshine can be a danger.

You should also switch off the lighting in the aquarium, as it naturally always produces a little heat. In the case of lighting with LED technology, this may still be low, but with conventional fluorescent tubes the temperature quickly increases by a few degrees.

Small water changes

In a very small aquarium, adding a few ice cubes to the water will help. In the case of a large amount of water, this is just the said drop in the bucket. It is similar with a water change. If you fill in cool tap water and take out warm water, this is also only practicable up to a certain aquarium size. However, this is the quickest and most effective measure in the event of a heat emergency.


First of all, the cover of the aquarium should remain open, because this way more water evaporates and this evaporation cools the tank down a little. This measure can be supported and strengthened considerably by a fan that blows directly onto the water.

But place a sturdy metal fly screen with a small wooden frame on the aquarium. Some fish tend to jump out, which would be fatal directly into the fan. The fan itself can tip over into the water and cause a dangerous short circuit.

Supply oxygen

A membrane pump or an aerator can effectively save the life of the fish when the water is too warm. The water temperature is usually less of a problem for them than the insufficient oxygen that is present in the warm water.

Cooling - shading - saving lives

  • Donate shade
  • Introduce oxygen
  • Cooling the water surface by fans
  • Partially change the water
Tips & Tricks If you repeatedly have problems with warm water, you should definitely replace the fluorescent tubes of the lighting with LED lighting. In addition, you can build a higher, airy summer cover from computer fans, which you put on in the warm season. Similar constructions are already available for aquariums in the trade.