Last update: November 4, 2022

Aquarium Heater Guards: No More Accidental Breaks or Burns!

I have seen thousands of different aquariums in my 30+ years of fishkeeping. But I can count on one hand the number I have seen with heater guards.

While heater guards might not be common, there is no denying that they are a very useful piece of aquarium equipment – in certain circumstances, at least.

Today, I am going to teach you everything you need to know about heater guards and even show you one that fits most heaters on the market.

What is a heater guard?

Small heater guard for aquarium

Typically made of plastic, a heater guard is a plastic cover that slides over your aquarium heater.

The holes in the cover aren’t just for looks. They allow the heater to warm the water as usual. Without these holes, your heater wouldn’t be as effective.

Think of a heater guard as a shield for your aquarium. It adds an extra layer of protection for you and your fish.

Do you need an aquarium heater guard?

Heater guards are perhaps one of the most situationally useful aquarium products around.

Does everyone need one? Definitely not.

But there are a few circumstances where adding some protection to your aquarium heater could be useful…

1. To protect your heater

Glass. It’s fragile. Unfortunately, it’s the material of choice for many aquarium heaters. I don’t have to tell you that it’s no match for heavy aquarium decorations, such as rocks.

Let’s say you bump a rock while cleaning your tank, if it falls against your heater, there is good chance it will shatter. And, you don’t want to spend your afternoon picking shards of glass out of your aquarium, right?

If you are clumsy, or have your heater against decorations that could fall, a heater guard could be a handy piece of equipment.

But if it was up to me, I’d recommend that you buy a shatter-proof heater instead, such as the Cobalt Neo-Therm.

2. To protect dumb fish

Most fish won’t even go near your heater. They know better. But some are not so bright…

Years ago, I had a pleco. His name was Potato… This is what happens when your three-year-old daughter names your fish! Anyway, it turned out that he was as bright as his name.

You see, even with all the different hiding spots I had in my tank, he loved nothing more than hiding behind the aquarium heater. And yeah, he got burned. Badly.

Pleco burned by aquarium heater


After a few weeks in a hospital tank, I returned him to his home. An hour later, he was back behind the heater.

Anyway, long story short… To save this dumb pleco from himself, I had to buy a heater guard so that he wasn’t pressed up against the hot outer glass of the heater.

Other fish, like oscars, have even been known to attack aquarium heaters.

This is pretty much the only scenario where I recommend buying a heater guard. Alternatively, you could always try an inline heater, which is a heater that sits on the outside of your tank. Your fish won’t be able to get to that!

3. To protect you

How much do you like your hands? Lots? I thought so!

Brushing against your heater by accident can be painful.

If you are clumsy, a heater guard could save you from a nasty burn. However, I would suggest using a good pair of gloves instead.

Aquarium heater guard review

Long plastic aquarium heater with suction cups

I’ll be straight up. When it comes to heater guards, there are not a lot of choices. In fact, when writing this guide, there was only one design on the market.

Seeing nothing to lose, I decided to try my luck with a generic heater guard by Uxcell.

This one, to be precise…

Plastic heater guard for aquarium heater protection

Straight up, I was put off by how long this thing is. At 16.5 inches long, it was waaaaaaaay longer than my aquarium heater.

Fortunately, this heater guard is adjustable. You see, it is made up of multiple pieces, allowing you to adjust the length to that of your heater.

At first, it didn’t feel like the pieces were going to come apart without breaking. But a quick tug was all it took to separate each section of the guard.

Here is what it looks like when all the pieces are separated…

Black plastic heater guard broken down into pieces

First, you have the top piece…

Aquarium heater guard top piece

The top piece is the largest, measuring 3.64 inches. It also has a cut out, allowing you to view the temperature settings on certain aquarium heaters.

Next up are the middle pieces…

Aquarium heater guard middle piece

All told, there are four of these in the box. Each piece measures 2.4 inches.

Finally, you have the bottom piece…

Aquarium heater guard bottom piece

Measuring 3.54 inches, this piece caps off the heater guard.

I was impressed by the modular design. It allows you to mix and match the pieces in any order you choose to fit your specific aquarium heater.

Check it out…

Long aquarium heater guard next to short one

So, I grabbed the nearest aquarium heater to me, a 150W Hydor Theo, and set about creating a heater guard to fit it.

Aquarium heater guard next to heater

And in less than a minute, I was done. Now all that was left was to slide the heater inside…

Inserting an aquarium heater inside of a plastic heater guard

It effortlessly slid inside.

However, it didn’t quite reach the end of the guard…

Aquarium heater inside of heater guard

Not that this was an issue. With the heater held firmly in place inside the guard, I simply needed to set up my protected heater in my aquarium.

And I was happy with the results. The suction cups held strong, the guard didn’t melt and the heater was now shielded. Everything I could ask for in a heater guard!

There is no denying that it’s easy to be the best heater guard when there is no competition. But even so, I was satisfied with how well it worked.

Want this heater guard for your heater? Grab it here.


Again, a heater guard definitely isn’t for everyone.

More often than not, the very job of the heater guard can be replaced with more functional equipment, such as gloves or a shatter-proof heater.

But if you have a fish that is in love with your heater, then it may be your only choice.

Do you use a heater guard in your aquarium? Let me know in the comments below!

Ian Sterling

I've been keeping fish for over 30 years and currently have 4 different aquariums – it's an addiction. I'm here to teach you everything there is to know about fishkeeping.

I also use this site as an excuse to spend lots of money on testing and reviewing different aquarium products! You can find my reviews here.

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