keeping an aquarium cool

7 Steps To Keep An Aquarium Cool In Hot Weather

how to cool your aquarium in hot weather

When it comes to keeping aquariums at the right temperature, there is no doubt that heating them is far simpler than cooling them down. Low temperatures can be dealt with by simply turning your heater up. However, you can’t deal with temperature highs by just turning heaters down. Learn how to keep your aquarium cool in hot weather.

Rather, you need some alternative, perhaps even ingenious solution, to deal with the problem of heat. This is where we can help you, with our guide to keeping your aquarium cool.

How to keep your aquarium cool in hot weather: Hot weather can be very detrimental to your home aquarium. It can unsettle the stable water conditions and temperature. Reduce the water temperature by either moving, cooling or aerating the water. Read our 7 simple steps to reduce water temperature.

7 Steps To Keep An Aquarium Cool In Hot Weather 1

How Hot Is Too Hot?

Like many questions in fishkeeping, there is no exact answer to this one. Tropical and coldwater fish species alike, thrive in a variety of temperatures. Angelfish, Mollies, and Guppies, for example, love the heat; 81F or 27C and Clown loaches love it even hotter at 86F or 30C.

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As a general rule of thumb, you can be safe in the knowledge that as long as your aquarium doesn’t exceed temperatures of 86F or 30C for weeks on end, there is no need to be concerned. However, temperatures above this and for extended periods will need to be addressed.

Why Are Excessively High Temperatures Bad For An Aquarium?

It’s not rocket science to know that your fish need to breathe oxygen to survive. The oxygen they breathe comes from within their aquarium water. However, as air temperatures rise, so does the temperature in your aquarium and oxygen saturation falls.

This fall, in turn, can lead to your fish struggling to breathe and puts them under a lot of stress. You will see them, during hot periods, frequently swimming to the surface in order to grab some air.

You may also notice more rapid gill and mouth movement. This is an indication they are struggling. Fish CANNOT withstand an environment as unfriendly as this for prolonged periods of time. 

Goldfish Gasping For Air
Gasping at the surface is a sure sign of low oxygen or unstable temperatures

How Do You Cool Your Aquarium Down?

Before you can cool your aquarium down, you need to know that the temperature is too high. This is where a reliable, and possibly permanent, aquarium thermometer comes into play. Regular temperature monitoring, especially during summer, is vital to your fish’s wellbeing and can help you prevent a disaster occurring. 

On spotting readings that are too high, for prolonged periods, there are several steps you can take to cool your aquarium down and relieve your fish’s stress. These are:

Turn your heater off

If you have a heater with a thermostat set to the optimum temperature you shouldn’t really need to do this. However, it is a way of ensuring your heater doesn’t add any extra heat and cause your fish further undue stress. Be careful to remember to switch the heater back on when the heatwave ends, or if temperatures will fall during the night.

Install an aerator

Doing so will improve gas exchange at the surface and maximize the dissolved oxygen content in the water helping your fish to breathe easier. Many aquarists choose to run these on a 24/7 basis anyway to maximize oxygen all year round. 

For a list of the quietest aquarium air pumps click here!

Keep lights on your aquarium to a minimum

Be it natural sunlight or your aquariums lights, both will add heat to your tank’s water. Keep the lights switched off and curtains closed to minimize these sources of heat.

Remove aquarium hoods and lids

Hoods and lids can be harmful twice over when it comes to heatwaves. Not only do they prevent heat from escaping from within your aquarium, but they can also inhibit oxygen exchange. Take care, however, when removing hoods/lids if you have fish that may jump out or pets that may jump in. You don’t want to lose fish due to removing lids and hoods, rather than helping them to survive.

Blow a fan across the aquarium’s surface

Just like removing hoods and lids, blowing a fan has multiple benefits. Firstly, it will help create water movement and help with aeration. Secondly, it will cool the water down. Be careful, however, not to use an over-powerful fan that will cause tidal waves in your aquarium. Ensure you always position the fan securely.

Float ice packs

By far and away this is the most popular method used to keep aquarium temperatures down. You can use ice bags, packs, even bottles filled with frozen water to implement this. You should not, however, put ice cubes directly into your tank. This is because the water they are made from will not have been treated and may cause harm to your fish.

We fill 1-liter bottles of water overnight then float them on top of the aquarium. We then replace them every few hours as needed until the water temperature has reduced.

Daily cool water changes

This is another popular way to cool an aquarium down. You should use water that is around 70F, and that has been treated with a dechlorinator beforehand. Around 30% of your aquarium’s volume is an ideal amount to exchange. 

Conclusion: 7 Steps To Keep Your Aquarium Cool In Hot Weather

Dependent on where you live, you may never come across and hence have to deal with high temperatures in your aquarium. However, as with anything, it pays to be prepared, and we hope with this article you will be just that!

Carl Broadbent