Most pet fish can handle temperature spikes just like they would in the wild. Even cold water fish (like Goldfish) can cope with elevated temperatures temporarily. Other fish are more sensitive to change and require temperature stability, such as many marine fish and some fresh water Goodeid species.

Any fish will be stressed to some point by significant increases in fish tank temperature, be it from the lower dissolved oxygen, increased rate of waste decomposition, or metabolic changes.  The more healthy your fish is to begin with, the better they will cope with any stressful situation, including temperature fluctuations.  Keeping the environment clean and feeding a natural diet (live, fresh, freeze-dried or frozen whole food) is the basis of a strong, healthy fish.

Following are 8 tips for keeping your aquarium cool as the temperatures rise this Summer:

  1. Keep the lights off and/or invest in lights that create little heat, such as LED aquarium lights.
  2. Ensure no direct sunlight hits the aquarium.
  3. Do small-medium water changes using water that is a couple of degrees cooler than your aquarium thermometer shows.
  4. Remove the hood and position a fan so it blows across the surface of the aquarium or sump. If you have fish that jump, cover with eggcrate, window screen or mesh. A mesh laundry bag from the dollar store works just fine for smaller tanks, just make sure it’s colorfast and soak it to remove any chemicals. The fan must be stable so there is no possibility of it falling into the water.
  5. Water movement cools through evaporation and helps to oxygenate the fish’s environment. Warmer water has less dissolved oxygen. Be cautious with fish that don’t like a lot of water movement, such as long-finned varieties.
  6. Increasing filtration can help in two ways. Warmer water may result in an accelerated waste decomposition rate that can crash your bio-system. An increase in filter power can prevent these issues. However, we still recommend you feed less during hot weather. Increasing filtration will also provide more water movement. Make sure your aquarium isn’t over-stocked to ensure there is enough oxygen to go around and the waste doesn’t overwhelm the bio-filter, causing ammonia spikes and crashing pH.
  7. In extreme cases, you can add frozen bottles of water (or dechlorinated ice cubes in smaller fish tanks) to lower the aquarium temperature. Ice packs should only be used if they’re sealed in a leak-proof bag to prevent accidental contamination. Keep a very close eye on the aquarium thermometer if you use this method, to ensure the temperature is not dropping too fast or too far.
  8. Buying an aquarium “chiller” is an expensive option, usually reserved for saltwater aquariums. You can buy an air conditioner for the same price or less and keep yourself cool too. However, a chiller offers better temperature control and auto stability, which can be priceless for delicate fish.

Natural Ways to Keep Aquariums Cool - Infographic

How do you keep your fish cool in the Summer? Please share in the comments below.

✔ You may also be interested in reading:
Natural Fish Food for Fancy Fins
Study: Garlic Fights Fish Flukes (With DIY Garlic Extract Guide)
Increase or Decrease Freshwater Aquarium pH Naturally


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2 thoughts on “Natural Ways to Keep Aquariums Cool (With Infographic)

  1. You’re a lifesaver!!!!! We’re getting a heatwave next wweek and I’m scared to DEATH that I’m going to lose my saltwater fish & corals!!!

  2. Most of the suggested are common knowledge but a couple are new ideas to me. I’ve been keeping fish on & off for 10 years or so. Pretty presentation!

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