The Best Filter For A Betta

What’s the Best Filter for a Betta?

There is no particular filtration unit that is ‘the best’ for a betta. There are several factors to consider when choosing a filter, including size, output rate, plants, tank mates, and the extent to which it will keep your aquarium clean. Therefore the ‘best filter for a betta’ will depend on your aquarium set up.

In this article we will talk about the different scenarios in which you could be choosing a filter, and present some advice that should help you to make a decision when it comes to buying.

At the moment there are several filters we recommend, although it is useful to consider these recommendations within the context of the rest of this article, and to some extent our other article: do betta fish need a filter?

So for the impatient amongst you here are our recommendations, but please read the rest of the article to understand more about betta filtration:

Advice on choosing A Filter For your Betta

So, on to how to choose the best filter for a betta.

We've included our own recommendations for a good filter above, but if you don't like the look of these and plan to choose a different one, here is some advice to help you with your decision.

Experimentation is important!

Something to bear in mind when it comes to betta care (and fish keeping in general) is that there is no set way of doing things. There are certain practices that you should follow, but betta keeping also involves some degree of experimentation. This is very true of filtration — there are different things that you can try in order to achieve the optimum solution for your particular aquarium. What we’ve included below is advice based on our own experience, but we do urge you to do further research yourself.

We love to hear about the setups that other people have created, so do let us know about your filtration system, or any other aspect of betta keeping that you would like to talk about.

The best filter for a betta will have these features:

• A slow output/current so the fish can relax and swim easily in the aquarium.
• An easy-to-remove cartridge system – the filtration media can easily be replaced when needed, and on an individual basis.
• Removal performance – will the filter be able to do it’s job given the size of your aquarium? Will it be capable of cycling the aquarium successfully and will it remove unwanted chemicals and waste?
• Filter media – does it have more than one media? In some cases, having all three types of media (mechanical, bio, and chemical) is better. In other cases (such as for optimal plant growth), just having one or two is better. We cover this in more detail below.
• Reliability – Will the filter consistently perform? Is it likely to clog-up or break down? Is it manufactured well? Always take other people’s’ experience with specific products into account when choosing a filter.

Other Important things to consider

The size of your aquarium. You may pick up a filter that is perfect in terms of the filtration mediums that it offers, but has a strong output rate. A strong output rate may not be an issue if you have a large aquarium, but can be a problem if your tank is small. In a large aquarium there will be areas where a current does not affect the water, nor create ripples on the water’s surface, which will be a suitable environment for your betta as there will be parts of the aquarium where it can escape the current, and therefore it won’t be stressed.

‍Does the filter have an adjustable output? It’s important to adjust the output of a filter in relation to the aquarium size. If you add a filter with a strong output to a small aquarium, it will stress your betta. It’s therefore important that your filter either has the option for the output to be adjusted, or that you can modify the filter yourself (see our article on filter baffling) in order to control the output.

‍Aesthetics & Practicality. Others features that are not important to the well-being of the fish but may be important to the keeper are aesthetics and practicality. Does the filter look good? Will the filter be noisy? Will it disturb you if the filter were to make noise because of trickling, the sound of the pump, etc.? These concerns are of course secondary to the well-being of your fish, but they are still worth taking into consideration when you buy a filter.

Filter media

The typical aquarium filtration system will be comprised of three different mediums; biological, mechanical and chemical. Each one of these mediums does its own job, you can read about how they work on our page: do betta fish need a filter?

‍Ideally you want to be able to replace each type of media individually because each medium needs to be replaced at different intervals. This is why a filter with separate inserts is often preferable to a filter that uses cartridges, which we explain in more detail below.

The optimum filter for a betta will contain all three mediums, although a filter with only 1 or 2 of the mediums can still perform well depending on your set up. Whilst the typical filter will be shipped with all three mediums, there are some filters that are only shipped with one or two. We’ll talk about this in more detail below, but first of all let’s look in more detail at why a cartridge filter isn’t always optimum.

Why a cartridge isn’t always optimum

Most aquarium filters these days come with all 3 filtration mediums, which is referred to as 3-stage filtration. The three mediums are known as mechanical, biological and chemical. It’s pretty standard for any built-in aquarium filter to have all three mediums, with each being easily removable and replaceable.

You may, however, come across a filter that has a replaceable cartridge. The cartridge will be manufactured by the aquatics company to fit the filter in question. Beware, though; replaceable cartridges aren’t always the best option because they can be impractical when it comes to changing the mediums at different intervals. Whilst they have been manufactured with the convenience of the fish-keeper in mind (because theoretically it’s easier to just slot in a new cartridge than it is to replace each medium individually), this can limit the control you have over the chemistry of your water. In our list of recommended filters below, we have taken this into consideration.

If you want maximum control over your betta’s water quality, it’s best to aim for a filter that has removable and replaceable individual inserts.

Filter Cartridges and Maintenance

Some filters will need to have their cartridge or inserts changed every month or so. The cartridge can vary from filter to filter, but typically a replaceable-cartridge filter will have a carbon or carbon-mixed cartridge that will need replacing periodically. Carbon is a great medium for removing toxins from the water, but if it’s not removed on a monthly bases it can actually create a backlog and the toxins can leak back into the aquarium.

The sponge insert can vary in size in any filter. When it should be rinsed/cleaned will be dependant on the amount of livestock in your aquarium. The more livestock, the more often it should be rinsed. The mechanical sponge is a place for beneficial bacteria to flourish in the filter, that’s why it’s best not to replace it. In fact, it only needs to be replaced if it gets withered over time. It should only ever be removed, rinsed (with freshwater) and reinserted. Most mechanical filtration media is hardy and isn’t designed to wither, and it usually lasts for years at a time. The same goes for biological media — nothing lasts forever but it should rarely be replaced, if at all. Over time biological media may become decrepit, but it will take years for this to happen.

Aquatics companies manufacture cartridge filters in different ways, but it’s generally agreed upon that a cartridge filter is second best to a filter that allows inserts for separate mediums. See our filtration page for definitions of this terminology and explanatory diagrams.

Choosing a filter

Now that we’ve covered the various aspects of filtration that you need to be aware of, let’s have a look at the scenarios in which you may be choosing a new betta filter.

Scenario 1: Choosing an aquarium with a built-in filter

If you’re buying a tank that comes with a filter built-in, you need to do some research to check that both the filter and tank will be suitable for the setup that you want. For instance, you may wish to check that the filter has a cartridge with separate inserts for each medium, as opposed to two mediums combined within one cartridge. This shouldn’t be the case for most tanks that come with a filter built-in, but it’s worth checking.

The majority of standard freshwater aquarium filters, especially those pre-fitted in an aquarium, tend to contain a biological, mechanical and chemical medium. From our experience, most of the built-in filters in the the Fluval freshwater aquarium range have all 3 mediums in their filtration. This will work great so long as you take into consideration how each medium affects the chemistry of the water.

We've used the Fluval Spec for keeping a betta and recommend it as a good option for a tank with a built-in filter. You can view it here on Amazon.

The typical filtration system should come with a carbon insert. The carbon removes organic compounds from the aquarium water, along with any other unwanted chemicals, if built up overtime can be harmful. This insert should be replaced every month or two. Aquarium plants love these organic compounds however, they consume them as a somewhat fertiliser and need it in order to thrive. When keeping aquarium plants, it’s also a great idea to give them a chemical plant feed. Having a carbon insert in your filter is not a great idea if you want to encourage plant growth.

‍If your filter has sponge, bio media and carbon inserts, you could replace the carbon insert with more sponge or bio media if you plan to keep live plants. When removing the carbon from the filtration, the plants will counteract this and act as filtration themselves. Aquarium plants are a great natural filter. You can read about this in our plants article.

‍To give you a real-life example, we bought the Fluval 19L for our current bettaWe wanted to be able to remove the carbon (the chemical medium) from the filter in order to encourage optimal plant growth. This is easily possible with the filter that’s built into the Fluval 19L, which is one of the reasons that we chose it. The built-in filtration is mechanical, bio and chemical. It comes with a sponge insert + 2 inserts: one for a bio sack and the other for a carbon sack. The carbon sack can easily be removed or replaced, which is what we did with ours. Basically the Fluval 19L gave us flexibility. It’s a great ‘works out of the box’ solution for betta keepers. You can remove the carbon if you want plant growth, or you can leave it in if you don’t intend to keep live plants and would prefer to keep the chemical medium.

Another reason that we like the Fluval 19L is because its filter comes with an adjustable output. The output on its lowest setting, combined with the 19L volume of the tank, creates a stress-free living space for a betta. The output nozzle is also adjustable, so it can be angled in a particular direction in order to further control the location and level of the current.

Remember, a betta fish is hardy and can live happily in various water conditions, but some other critters can be quite particular when it comes to an aquarium environment. A betta fish could live happily with just a sponge filter, provided that you replace the insert every month or so and carry out regular water changes. If you plan to keep other inhabitants with your betta, you may need to invest in a filter that can sustain a suitable water condition for the whole ecology of the aquarium. This also brings up the fact that the more critters you have in the aquarium, the more waste there will be, meaning more ammonia, nitrites and nitrates will occur. Your filter needs to be able to handle this.

Scenario 2: adding a filter to an existing aquarium

The other scenario is that your tank does not have a filter built-in, in which case you need to choose one to add to it. Which filter you choose will dictate the amount of control you have over replacing the three filter mediums individually. For example, if you choose a filter that uses an all-in-one cartridge, you may be forced to replace the biological medium at the same time as the chemical medium. This isn’t ideal — we explain why in more detail below. If you choose a filter that houses its media in separate inserts (or has a cartridge that can be modified so that you can replace the mediums at different intervals), you maintain the ability to replace them individually and ultimately this provides more control and flexibility.

There are quite a few great value aquariums on the market that are manufactured specifically with bettas in mind. This means that they come with a filtration unit that’s also great for bettas in terms of size, practicality and filter mediums (you can view some examples aquariums in our best betta tanks article). This may not be the case when buying a separate filter for your betta with the intention of adding it to an existing aquarium. It’s certainly not impossible, but there are a few factors that you need to take into consideration.

For example, if you’re adding a filter to your aquarium, it can be a challenge to find a suitable filtration unit for a water volume that’s less than 5 gallons that won’t create a strong current and that won’t be bulky in the aquarium. This is yet another reason why it’s best for you to keep a betta in an aquarium with a capacity of 5 gallons or more.

Below we have listed some good filters for betta tanks, and we explain how they work in regards to replacing the three different filter mediums. We’ve also included some of the other pros and cons so that you can choose the appropriate one based on your setup and budget.

Filters that we recommend

Hopefully we’ve explained enough of the theory behind betta filtration that you can now make an informed choice about choosing a new filter. While it’s difficult to simply recommend the best filter for a betta, the  choices that we present below take into account the following:

• Reliability, durability – does it do a good job?
• Media replacement – are the mediums easy to rinse/replace on an individual basis?
• Output – does it create a strong current? does it disturb the surface of the water? If so can it be baffled easily?
• Size – will it fit into a 19L aquarium comfortably?
• Noise – how much noise does the filter make? Does it become noisy after extended use?

Cascade 300 Submersible Aquarium Filter by Penn-Plax

The nozzle on this filter as well as the pump makes the output flow easily adjustable and easy to baffle to be able to make the most comfortable home for your betta.

Another perk of this filtration unit is that it doesn’t use an all-in-one cartridge – you can control and replace each medium individually, which is great for keeping a consistent water quality.

It does create a quiet hum but isn't terribly loud.

View it here on Amazon.

Bio-Wheel Power Filter by MarineLand

This is a nifty little filter due to how it defuses oxygen into the water by vigorously disturbing the water with a wheel inside the filter unit rather than inside the aquarium which would typically stress a betta.
This technology also feed the beneficial bacteria inside a healthy amount of oxygen which helps with the maintenance of the colony. Again, very reliable and does the job of filtration well.

However it is a hang-on filter; it cannot be submerged and may not be compatible with an aquarium with a fitted hood or lid. It also is a cartridge filter and specific cartridges need to be bought for it. It doesn't hum but you can hear the ripples/splashes of the oxygenating wheel in the filter.

View it here on Amazon.

Hagen – AquaClear 20 Power Filter

If you want a quiet filter this is probably as good as it gets. No filter is completely silent, but the Hagen AquaClear 20 Power Filter does a pretty good job of keeping noise to a minimum.

Another perk of this filtration unit is that it doesn’t use an all-in-one cartridge – you can control and replace each medium individually, which is great for keeping a consistent water quality.

View it here on Amazon.

BETTA 150 Aquarium Fish Tank Internal Filter

Like the Cascade above - the nozzle and pump on this filter makes the output flow easily adjustable and easy to baffle. Another advantage of this filtration unit is that it doesn’t use an all-in-one cartridge. We found this filter to be extremely easy to use and reliable.
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One down side is that it only ships to the UK and Europe currently. You can view it here on Amazon.co.uk.