How to Keep A Tropical Fish Tank Cool in Hot Weather

By Eddie Waithaka @aquariawise

How to Keep A Tropical Fish Tank Cool in Hot Weather

Keeping your aquarium cool does not seem like a challenge considering it is a tank full of water, yes?

Well, for the most part, it’s not.

If anything, you’ll most times be struggling to keep your tropical aquarium warm, especially if you live in temperate regions.

However, this bliss takes a turn in hot weather, more so during summer with frequent heatwaves in most places north of the equator.

You might not notice your fish struggling at first since most tropical species can handle a reasonably high water temperature, but if the scale tips past 84 degrees Fahrenheit, then you will start having trouble.

Your tank won’t have enough oxygen dissolving in the water, plus the increased temperature will cause your finnies discomfort.

So, how do I cool my tropical fish tank in hot summer weather?

The first thing I do is check my aquarium water temperature. If the reading is above 84 degrees Fahrenheit, I’ll switch off the heater and move my tank to a cool spot in the house away from windows and direct sunlight.

I then prepare several ice packs to use in the tank if the water temperature keeps going up. I make sure to bring down the temperature gently because huge variations are worse than a high reading.

Since warm water has less air, I also add an air pump with a bubbler or wavemaker to aerate my fish tank and keep my fish from suffocating.

Now, if you have this problem every time summer rolls over, consider saving a couple of hundred bucks to invest in an aquarium chiller. It will come in handy anytime you have elusive heat readings in your tank.

Keeping Your Aquarium Cool in Hot Summer Weather

Perhaps using ice packs to cool your fish tank during hot summer weather is the simplest and fastest way, but several other hacks work equally well.

Combaning more than one solution will more likely have better results as well.

One of these tricks (and probably what you should start with) is to open your aquarium’s lid and position a fan to blow across the water surface.

You’ll also want to couple that with an aerator to improve gas exchange in your tank, which is helpful, especially when you only have a small increase in temperature.

Next, turn off your aquarium lights and move your fish tank away from sunlight, heater, and any other appliance that might warm up your fish tank.

Remember to turn off your fish tank heater as well, but make sure you implement each step in a controlled manner to ensure the readings don’t drop too drastically.

Only when you’ve gone through all these steps do I recommend placing ice packs in your water or plugging your aquarium chiller.

How Can I Keep My Aquarium Cool Without A Chiller

Perhpas, you’ll see most of the points on the subheading above repeated here since the two querries are somewhat the same.

Essentially, all the hacks I’ve mentioned (above) are ideal solutions when you don’t have a chiller for your fish tank.

Here is a quick list of things to do to keep your fish tank cool without a heater (as I’ve demonstrated in the preceding paragraph).

Can I Put Ice Cubes in My Fish Tank During Hot Weather

Floating an ice pack in your fish tank during hot weather is a brilliant way of bringing the water temperature down.

However, you should not add ice into your aquarium directly, more so if not prepared with dechlorinated or reverse osmosis water.

Moreover, placing packs of cold water or ice one at a time while keeping tabs on the readings is a more reasonable approach because then the temperature will reduce gradually.

Ideally, you only want a 3 to 4 degrees decrease in temperature every 4 to 5 hours.

How Hot is too Hot for Your Tropical Aquarium Fish

Most tropical fish prefer an aquarium temperature anywhere from 72 and 82 degrees Fahrenheit.

However, some species like goldfish, mountain minnows, zebra danios, and weather loaches may live (and even do better) in cooler water (between 60 and 70 degrees Fahrenheit).

On the flip side, Discus and a few other tropical aquarium fish can survive at up to 86 degrees Fahrenheit, but they’re not many.

Most species will start struggling at a temperature higher than this and will start dying at 90 degrees Fahrenheit, starting with stressed, sick, or injured finnies.

That said, although high water temperature can kill aquarium fish, significant variations will kill them much faster. So, make sure when warming or cooling your fish tank, you do it gradually.

Now, a question I get often is whether 28 degrees Celcius (82 F) is too hot for tropical fish.

Well, yes and no.

28 degrees Celcius (82F) is on the higher end of most fish kept in home aquariums, such as betta, guppies, tetras, angelfish, cories, and killifish, but for species like Discus, it is right up their alley.

Goldfish, danios, white cloud minnows, Weather loaches, and other cool water tropical fish will struggle and most likely die at 28 C (82 F) because they are used to lower temperatures.

Can Tropical Fish Get Too Hot in A Fish Tank

Yes, it is possible for tropical fish in a tank to get too hot. Essentially, any temperature above 90 degrees Fahrenheit will strain even the hardiest fish, and most will succumb if you continue keeping them in such conditions.

Most of the cases I’ve heard have to do with faulty meter as opposed to the owner intentionally heating a fish to that level unless when doing heat treatment on ich.

For this reason, you will want to have at least two thermometers in your fish tank on either end to remain aware of your fish tank temperature at all times and note if a meter becomes faulty.

That’s all for this post.

Enjoy keeping finnies🐠🐟.

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