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How To Keep An Aquarium Cool: 7 Ways You Can Try Today

Lindsey Stanton Profile Picture

By Lindsey Stanton

Clown fish in aquarium tank

The temperature of an aquarium is always a big deal when it comes to keeping fish. Some fish like their water to be warmer, while others need it to be on the cooler side of things. Heating an aquarium is one thing and is not too hard to do.

However, on the other hand, keeping an aquarium cool can be a little more challenging, especially if you need to cool it down. How to keep an aquarium cool is what we are here to talk about today.

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The 7 Ways To Keep An Aquarium Cool

1. Keep Aquarium Lights Off

One of the best things that you can do to keep your aquarium water cool is to keep the lights turned off as much as possible. Strong and bright aquarium lights, especially those that use a lot of energy, can get got fast. The heat created by the light, as well as the heat energy from the light itself, can both raise water temperatures.

Now, this might be a little difficult because you may have plants or fish that need a lot of light. However, there is a solution to this. There are many aquarium lights out there that produce no or minimal heat.

Okay, so most of them do produce some amount of heat, but some way less than others. You need to find aquarium lights that are not too bad in terms of heat production (we have covered a good buying guide here), and when possible, keep them turned off. For instance, instead of having the lights on for 12 hours per day, you can have them on for 7 or 8 hours per day. Sure, it might slow down plant growth a bit, but at least you won’t overheat the fish tank.

2. Place The Tank Low

The fact of the matter is that heat rises upwards, so the higher up your fish tank is, the warmer it should be. Now, this can be a little difficult because you might live in an apartment or on the second or third story of a home. However, if you can, try to put your aquarium on a floor that is lower down in the house, even in the basement if possible (if you have a basement that is nice and clean).

At any rate, having a fish tank on the top floor during the summer, or even in the winter when you are heating the home, is going to make it hard to keep the temperature down. The lower you go, the easier it will be to keep your aquarium cool.

harlequin rasbora in aquarium
Image Credit: Arunee Rodloy, Shutterstock

3. No Direct Sunlight

We all know that the sun heats things, which is, after all, why we humans can live on the planet earth. That being said, if you need to keep your aquarium cool, always make sure that the tank does not get hit by direct sunlight. The sunlight will heat things, plus it will do you no favors in terms of controlling algae blooms.

Furthermore, if you can, keep the tank in a room that never gets hit by direct sunlight. The positioning here does depend on where on this planet you live, but if you can, keep the tank in a room that receives little or no light during the day. The sun can heat a room pretty quickly, which then leads to the heating up of the aquarium.

4. Removing Lids

Yet another thing that you can do to keep your aquarium cool is to remove the lid or hood from the tank if it has one to begin with. Glass and even plastic hoods and lids are notorious for magnifying light and heat. If you have an aquarium light or the tank gets hit by sunlight, the hood will amplify it and cause the water to heat up.

Just be careful that you don’t have any jumping fish that will escape if there is no lid on the tank. Even mesh lids can hold in a certain amount of heat, so your best bet is to remove them if you want the aquarium water to stay as cool as possible. This will allow heat to dissipate much faster than if your aquarium has a hood or lid on it.

aquarium cleaning
Image Credit: hedgehog94, Shutterstock

5. Fans

Another thing that you can do to keep your aquarium cool is to use a simple air fan (we have reviewed our top five here). Point the fan at the water and have the fan as level with the surface of the water as possible. Having an air fan blowing at the surface of the water will allow heat to dissipate from the top of the water.

It is one of the best possible methods for cooling down an aquarium and keeping it that way. Just make sure that you don’t place the fan anywhere where it can fall into the tank and potentially electrocute the fish.

6. Icing

Another thing that some people do to help keep aquarium water cool is to simply use some ice. Now, you do need to be careful doing this. While ice cubes and frozen water bottles will cool aquariums down, they also come with a risk. If you let the ice melt or the frozen bottle thaw, the water temperature can quickly rise again.

Temperature fluctuations are not good for fish, so you do need to be careful. If you are icing the water, make sure to always have more ice ready to go so that the water temperature is not constantly being raised and lowered. Make sure not to add so much ice that the water temperature drops down too low. This process takes a bit of trial and error to get right, a process where a reliable aquarium thermometer will help.

Gold fish aquarium
Image Credit: Janelle Lugge, Shutterstock

7. Electronics

Finally, if you have things like a protein skimmer, a filter, lights, pumps, aeration tools, UV sterilizers, and other such things, go for models that have a low rate of energy consumption. The bigger these aquarium accessories are and the more energy they use, the warmer they will make the water.

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Yes, there are lots of fish out there that need the water they live in to be fairly cool. As long as you use one or any combination of the above methods, you should have no problem keeping your aquarium water quite cool and at the ideal temperature for your fish.

Feature Image Credit: Jordan Tan, Shutterstock

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