5 Best Small Hang on Back (HOB) Filters

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Any aquarium needs a filter that can clean the water for a long time, without the need to replace it too soon. If you’re looking for a reliable water filter for your fish tank, you arrived on the perfect web page.

Today, I’ll tell you about the 5 best hang on back filters you can use with your aquarium. All of them are available on Amazon for purchase. But before you find out about these devices, I should let you know why a hang on back filter (HOB Filter) could be a good fit for your aquarium.

Why Choose a HOB Filter?

There are many different types of water filters that can be bought online. For instance, you could find canister filters, sponge filters, internal power filters or hang on back filters if you make a quick search.

But what makes HOB filters good for most people? I’ll tell you about 3 reasons why people like these devices, and probably you’ll feel the same way.

First, a HOB filter is easy to install, or mount when you first launch it. It doesn’t matter which item you’re going to choose from later in the article, all of them are simple to get started. Why?

Every HOB filter is simply clipped on to the back of the aquarium at hand. It doesn’t require anything else. When you clip it to the back of the tank, a lift tube will be lowered into the water.

This tube is going to suck the water into the filter, with the help of a little pump. When the water was cleaned entirely, using a spillway, it’s returned into the tank. And for all this to happen, you only need to clip the filter to the back of your fish tank. It doesn’t get easier than this.

The second reason for choosing a hang on back filter is the fact that it’s very efficient at cleaning the water. After all, that’s why you bought it, right?

Every HOB filter comes with a 3-stage filtration system that will clean the water mechanically, chemically and biologically. None of these systems should be missing, because they do the whole filtration together.

For instance, the mechanical media will capture all the solid debris floating in the aquarium. The biological filtration will take care of the ammonia and nitrates that are produced by the fish. If these substances remain in the water, the fish could get sick, and even die.

Last, the chemical filtration will get rid of all the remains that are left after the bio-filtration. This way, the water that leaves the filter is crystal clear where your fish can thrive.

The third reason to choose a HOB filter is the design and size of most such devices. When you buy a new water filter, you want one that looks good and doesn’t ruin the whole look of your beautiful aquarium, right? This is why a HOB filter is great.

They are designed to improve the design of your fish tank and most of them are compact and don’t require too much space.

Now that you know why a hang on back filter could be a good choice, let’s move on and talk about our 5 picks for the best HOB filters on the market:

1. AquaClear 20 Power Filter

The Aqua Clear HOB filter comes in multiple different sizes for different needs. You can choose between 5 versions, crafted to work with smaller or bigger aquariums depending on the volume in gallons.

The one I’m talking about is the Aqua Clear 20. It works with tanks that contain between 5 and 20 gallons of water. So, you have a pretty big interval in which you can use this device.

It includes all the must-have filter media types: mechanical, biological and chemical. Also, you should notice that a re-filtration system is implemented. This will offer a superior mechanical cleaning system, because a longer contact time is assured between the water and the mechanical media.

The water is sucked into the device using an energy efficient pump. Because of this pump, the running and maintenance cost lowers quite a bit.

If some problem emerges regarding the filter, you can send it back for free and they will take care of the problem, due to the 2-year warranty.


2. PennPlax Cascade 20

The second item on our list is the Penn Plax HOB filter. Just like the previous product, this one also comes in multiple versions, depending on the size of the fish tank. I will talk about the first version, called the Cascade 20.

This filter is suitable for an aquarium that has up to 7 gallons of water in it. During the span of 60 minutes, the filter can deliver 20 gallons of cleaned water in the tank. So, for example, if you have a 5-gallon aquarium, the water is going to be filtered 4 times during 1 hour.

It doesn’t matter if you have a fresh water environment, or a salt water one. The filter is designed to work in both cases properly. It includes an adjustable flow knob, that lets you reduce the filtration while your feeding the fish.

Also, the sponge inside the device is serving as a container for the bacteria colonies that take care of the bio-filtration of your water.


3. AZOO Aquarium Mignon Filter 150

This device is the next item worth checking out as a great HOB filter. How does it perform? The AZOO 150 is suitable for aquariums that contain up to 30 gallons of water. So, even bigger fish tanks are kept clean using this filter.

It comes with all 3 important filter media included in the package. Just like the previous device, this one also has a sponge inside it, that takes care of the mechanical filtration of solid debris.

Doing maintenance work for this device is as simple as it gets. You only need to take off the top cover, and take out the filter media, then rinse it with clean water. When you see that all the captured debris is off the media, you can place it back inside the filter.

Don’t forget to do the maintenance work, because this way you’ll ensure a better performance of the device, during a longer period.

The AZOO is also quite silent, so you can keep the tank in quiet rooms too, without worrying about loud noises coming from the device.


4. Boxtech Aquarium Hang on Filter

The Boxtech filter is available in 3 different sizes for different aquariums in terms of water volume. The most popular is the Boxtech 5-10 gallons. As you can probably tell, it’s suitable for 5 to 10 gallons of water fish tanks.

It’s built from a durable plastic material, that ensures a longer working period. This is especially true, if you clean the filter media on a regular basis. Usually, you can find the period for this in the user manual, or displayed on the box.

The water flow that comes out of the filter is adjustable. This allows for a better oxygenation of the water, and thus creating a suitable environment for all your marine life inside the tank.

The device is also very silent, like the one before. It won’t bother you, no matter where you place it.

And of course, the water flowing out of the device will be as clean as possible, due to the 3-stage filtration system put in place.


5. Tetra Whisper EX Silent Multi-Stage Power Filter

Here’s the last item on our list. The Tetra filter that I cover here was created for aquariums with up to 20-gallon in capacity. There are other versions as well, for bigger fish tanks, but this is the smallest.

It does all the filtration stages you’d expect from it very efficiently. But the main feature, that’s also present in its name, is how silent it is. The previous items are also good in this area, but this device is specifically created to work quietly, without bothering anyone in the room.

When you take it out of the box, you can use it right away. There is literally nothing you should do to assemble it. Like I said above, the only step you have to take, is to clip it to the back of the fish tank. The rest is up to the device to handle.

This is als0 a multi-stage filter, because it does all 3 filtration stages efficiently. Mostly, it works the same way like the previous items.



Now you know which items on Amazon are the best small HOB filters for your aquarium. The only thing left to do, is choose your personal winner.

This depends entirely on your specific needs. Just check the aquarium’s volume, and you can pick the perfect filter. This is what matters the most when choosing.

But whichever you may choose, any of the 5 devices in this article can do a great job at cleaning your aquarium water.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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