There’s no two ways about it, if you’ve got a fish tank, you’re going to need a filter. The natural biological processes of fish mean that, without a filter, your water will soon become polluted and your fish will get sick. Every aquarium, therefore, needs some type of filtration.
A filter’s job is to remove from the water of a tank various kinds of debris and impurities which can fairly rapidly accumulate. This can include things like excretions from the fish themselves, but also food debris and other foreign material that can enter the water from the surface. One of the most common household fish tank sizes, the 5 gallon fish tank filter can vary massive in other aspects.
Buying a filter can be a fairly confusing business; from HOB filters to undergravel filters or sponge filters there are many different kinds to choose from. What 5 gallon filter you ultimately go with will be decided by almost as many factors, from your tank volume to the type of aquatic life you want to support.
Keeping things simple is a good way to start. So sticking with filters designed for the five gallon tank, read for a rundown of ten of the best and some useful FAQs.
The 10 Best 5 Gallon Fish Tank Filter
1. Aqua Clear 20 | The Best HOB Filter
With this model, Aqua Clear has delivered a filter which is very impressive for the price you’ll pay for it. This filter performs well in all three of the main areas of filtration – mechanical, chemical and bacterial – and extends that versatility to other areas as well. The Aqua Clear 20 is designed for our five gallon tank but will be effective in tanks as large as 20 gallons.
An Aqua clear is fuss-free to install – needing only to be hanged on the side of the tank – and has some impressively innovative features to recommend it. For one thing, it preserves the beneficial bacteria in the form of a complex pore system in the filter where bacteria can thrive. The Aqua filter’s flow rate can be accurately controlled and, even at lower flow rates, can process around 50% of the water in the tank multiple times. This is due to a patented refiltration system.
At the maximum flow rate, this filter can be a little noisy, making it perhaps unsuitable for the bedroom! The intake on the filter is also big enough to pull in the very smallest fish so you’ll want to be careful on this count (although this will only be an issue with the very smallest fish or fry). Overall, however, this is an innovative filter for a very reasonable price.
- Ease of installation
- Preserves beneficial bacteria
- Innovative refiltration system
- Adjustable flow
- A little noisy at a maximum flow rate
2. Pen Plax Cascade 20 | Best for Multi-Functional Cartridges
Another very good hang on filter is the Pen Plax Cascade, which has much to recommend it. This filter has an adjustable flow, which is useful in many circumstances such as when feeding. The Cascade’s filter cartridges are very impressive, even though within this area there are also downsides. Although they can be pricey and will produce odor when the carbon is spent, they more than make up for these shortcomings with their impressive range of functions.
Made from Carbon and Poly-Fiber floss, these double-sided cartridges will at once catch particulate matter, remove toxic chemicals and reduce odor. It is largely down to this triple-pronged attack that this filter features on our list.
- Adjustable flow
- Multi-functional carbon/poly-fiber floss filter cartridges
- Suitable for fresh and saltwater
- Odors develop when carbon used up
3. Zoo Med Nano 10 | Best Small Canister Filter
Moving on from our hang-on models, the Zoo Med Nano is the first canister filter to feature on our list. Although canister filters are more associated with larger tanks, this particular model does a great job in a five gallon aquarium. It’s also highly affordable, which is surprising for a canister filter as these are most often the most expensive aquarium filters. Like all canister filters, it’s virtually silent.
Being designed for smaller tanks, this filter is also compact itself, leading to an ease of cleaning and storage whilst style offering the great media volume associated with canisters. The pump that comes with this canister, it must be said, is a little weak and it has been noted by some users that the sponge isn’t very effective inside the canister.
Overall, however, it’s great to be able to get a canister filter this size for a smaller tank.
- Small-tank canister filter
- Pump a little weak
4. Marina Power Filter | Best Budget Filter
For our smaller five gallon aquariums, prices are generally a good bit lower than with larger tanks. Yet, even so, this little number retails typically for a very reasonable price indeed. And for all that, there doesn’t seem to be any overt compromise on quality. Granted, this filter can clatter a bit but it has so much that you would not expect for this price, including even an adjustable flow rate.
The marina is also customizable, being large enough for the addition of extra media. And yet, even with that extra space, this filter is designed in such a way that it manages also to be slim and compact, leading to minimal physical disturbance of your tank.
- Very affordable
- Adjustable flow rate
- Downdraft created at a lower flow rate
5. Whisper in-Tank | Best Compact Design
This small, compact hang-on filter makes a selling point of its neat design. Yet this small cylindrical filter has much to recommend it beyond ease of storage and set up. For one thing, this is another highly affordable filter which is actually surprisingly quiet.
The hang-on filter also has a dual intake, which is a clever way of maximizing the efficiency of this filter’s small size. And that’s not the only way it is innovatively designed; this filter can also be mounted on the inside of the tank, meaning that the tank can be pushed flat against a wall. That said, herein lies a danger: the Whisper In-Tank filter can pour water out of its back, meaning it will wet your floor if you place it too high. This is a problem that can be solved by simply placing it further into the tank but it must be noted that users should be alerted about this. Being a smaller filter, it has the potential to burn out after a couple of years. That said. This filter is cheap enough to make rebuying a viable option.
- Small and compact
- Easy to install
- If placed too high will spill water
- A motor can burn out after a while
6. Aqueon Quietflow | The Best All-Rounder
With this filter we might be breaking our own rules; this one doesn’t actually come in a five gallon version (you’ll have to get the ten) but it makes our list of the best five gallon tank filters because, excelling in all three forms of filtration, this is a great all-rounder filter and probably the best to go with if you’re really lost as to what you need.
This filter includes two filter cartridges, which provide biological and mechanical/chemical filtration respectively. On top of this, it provides a sponge media for mechanical filtration as well. This is an impressive array in anyone’s book and it’s particularly impressive for a filter so compact. This filter is also very simple to set up and will reset itself if the power is interrupted, thanks to its auto-start pump. One pretty glaring downside, however is the discrepancy between this filter’s name and the reality of the sound it makes. It isn’t particularly “quiet”! Although far from being noisy, this is an almost comical misnomer.
- Set up and maintenance very easy
- Three types of filtration media
- Auto-start pump
- Can be loud
- The filter can clog quickly
7. Penn Plax World | The Best for Busy Fish-Owners
Another offering from Penn Plax, this filter is yet another that is exceptionally affordable, although you will require an air pump to make it work. This filter makes our list of the best five gallon tank filters because it is both cheap and easy to maintain. The filter cartridges last a good six to eight weeks and are cheap and easy to replace. This is what makes this filter such a good choice for those of us with a small fish tank who don’t have the time to be full-time marine zoo keepers! This model can be a little loud and bubbly but this is not excessive. Overall it’s a very good time and money saver.
- Very Affordable
- Can be instantly set up
- Cartridges last 6-8 weeks and are cheap
- Requires air pump
- Can be loud
8. Fluval Nano | Best with a Spray Bar
This model from Fluval stands out on our list because of the detachable spray bar which it comes with. This can be exceptionally useful for agitating the surface of the water to prevent a film or scum forming. Although this model has to be assembled, that is very easy to do. This model also has an adjustable flow rate and, spray bar aside is very compact.
Annoyingly, the Fluval Nano only offers mechanical and biological filtration. If you want to do something about odors or discoloration, therefore, you’ll need to purchase separately sold carbon cartridges – but at least that option is there. This model can be awkward to clean, but you won’t have to do that too often.
- Detachable Spray Bar
- Adjustable flow rate
- Easy to assemble
- Can be difficult to clean
- Only mechanical and biological filtration (carbon cartridge sold separately)
9. Tetra Whisper Power Filter | The Best for Preventing Build Up
Where a previous entry on our list boasted six to eight-month lasting cartridges, this model will, perhaps annoyingly, have you changing them monthly. However, if you’re up for the extra work, you’ll be rewarded with some very effective and innovative filtration technology. These cartridges offer chemical filtration that not only prevent odors and discoloration, but will prevent grimy build up on your glass.
Mechanical filtration is also aided by the double-sided mesh filters – quite simply, it can catch more. This is also a quiet filter although there have been some reports of it getting noisier over time. One hopes this is the result of faulty models and not a design flaw!
- Dual sided mesh filters
- “Stayclean” technology
- Cartridges need to be changed monthly
10. Azoo Mignon 60 | Best for Quietness
The Azoo Mignon 60 actually a great all-round filter – being compact, efficient and easy to use – but the real reason it’s on our list is that it is very quiet. The quietness, or lack thereof, is something we have mentioned with every filter on this list, and this one is the best.
Other benefits include handy compactness and ease of installation, as well as an adjustable flow rate. The sponges this model comes with, and therefore the mechanical filtration, are, however, pretty low quality – although you can always replace them. Also at maximum flow rate, it can be a little strong for smaller five in a five gallon tank. If you want silence, however, this is your filter.
- Easy to maintain
- Very Quiet
- Low-quality sponge filters
Best 5 Gallon Fish Tank Buying Guide
Before you buy a filter for your five gallon tank, there are of course a great many things to consider. A five gallon tank is, for one thing, one of the smallest that you could expect to use and for this reason, it is common amongst casual fish owners who simply keep a few small to medium-sized fish in the corner of their room. This has implications for what type of filter you should get. Read on for some helpful FAQs
Do I need a filter for a five gallon tank?
Yes. You will require a filter for any tank, from the smallest three gallon tank right up to massive 40 gallon aquariums. Without a filter, fish excretion builds up, water nutrients are used up and the environment becomes totally hostile to aquatic life.
Reminder: Do not forget about aquarium heater!
What is the best type of filter for a five gallon tank?
As you will have noticed from our list, you can use several types of filters in your five gallon tank, from hang-on to submersed models, from canisters to those requiring an air pump. That said, some are more common than others. The reason, for example, that there is only one canister filter on our list is that these are much more commonly used for larger tanks. This is also why they’re more expensive. With a five gallon, you can usually expect cheaper hang-on filters to be more than suitable.
Can you use a ten gallon filter in a five gallon tank?
Technically yes, and you might have noticed that one model on our list – the Aqueon Quietflow – is, in fact a ten gallon filter. This is not optimal, but an individual filter that is designed for larger tanks might well have other features that make it very suitable for your smaller tank, so don’t rule them out. Generally speaking, a ten gallon filter will process more water with a higher flow rate.
A flow rate that is too high can potentially cause dangerous currents in a smaller tank. With those filters with adjustable flow rates, however, this is a problem you can solve simply by turning it down. That said, it wouldn’t be advisable to go far beyond a ten gallon filter for a five gallon tank!