Do Betta Fish Need a Filter? (4 Important Reasons)

Bettas need filters in their tank; whether they are in a nano tank or a larger one with other fish, it has to have a filter.  

To raise a healthy betta, you must create a conducive environment similar to their natural habitat. While learning about filters sounds complicated, it’s essential to know this information for your betta’s good health.

Although bettas are tropical fish and can survive in muddy waters like those they are native to in Southeast Asia, it doesn’t mean they’re thriving. With predators lurking in the dirty water, bettas only live around four years in the wild. 

If you want them to live longer than 2-4 years without illness or stress, you must maintain good water conditions in the tank by using a filter. 

But what does it do? Read on to find out! 

What Does a Betta Fish Tank Filter Do? 

Aquarium filters allow water to enter the filter through a pump before pushing the water upwards, downwards, and sideways throughout your tank. The filters main purpose is to trap particles and remove them from the water so the water becomes clean and free of contaminants for your fish to thrive.

The most common filtration methods include biological, mechanical, and chemical, which we will discuss further below.

With each filter type serving a specific purpose, it’s easy to maintain the required water parameters and lengthen the lifespan of your betta fish.

Main Purpose of an Aquarium Filter

Although these fish are found in slow-moving waters, rice paddies, and often murky and muddy shallow streams, they still need filters to survive while in your home aquarium. The numerous plants and waste can act as a filter in their natural environment. 

The primary purpose of a filter in a betta tank is to keep the water healthy and clean for your bettas. A filter also helps oxygenate the water, eliminate harmful chemicals, and make the water suitable for your betta fish.

Without a filter, your betta’s water will become cloudy and cause them stress. The stress weakens your betta’s immune system, which only leaves the door open for other problems like diseases.

To avoid this, you can get a filter or change your existing aquarium filter so your betta can get some of the benefits listed below: 

4 Reasons To Use a Filter in a Betta Tank

If you still aren’t convinced that you and your betta fish need a filter, then here are four reasons why you should reconsider:

1. It keeps the tank water clean and flowing

Maintaining the proper aquarium water parameters is essential for any betta fish to survive. The water should be clean and constantly moving, which you can do with a filter in the tank. 

Filters will clean the tank water and remove solid particles and debris before it becomes toxic to your fish. You also don’t want stagnant water in your tank. 

In the wild, bettas are always in constantly moving water; It might be slow, but it’s not still. 

If the water isn’t moving around often, more carbon dioxide will be absorbed into the tank. Carbon dioxide isn’t suitable for the plants or fish in the tank that need oxygen to survive. 

2. It controls the ammonia and nitrite levels in the water

The biological breakdown of bacteria happens naturally in any freshwater tank. As part of the nitrogen cycle,  fish waste and uneaten food are broken down into ammonia in the fish tank.

High ammonia levels are poisonous to fish, but beneficial to bacteria growing in the betta’s tank.

A quality filter can maintain the proper ammonia levels without removing the helpful bacteria that fish need. The ammonia is broken down into nitrites which are further broken down to nitrates which are less harmful to fish.

Most beneficial bacteria will grow around biological media in the tank’s filter, thus limiting the ammonia and nitrate levels in the water. 

That is why many fishkeepers prefer using a filter instead of overly frequent water changes.  

Controlling this also reduces the likelihood of illnesses caused by poor water quality like ammonia poisoning or ich disease. 

3. It oxygenates the tank water

One of the main benefits of having a filter in your fish tank is that it helps oxygenate the water. Oxygen is essential for living things in the tank, like fish and plants. 

Although bettas have adapted to breathe air from the water’s surface, they still need enough oxygen in the water, where they spend 90% of their time. 

Water without oxygen can also quickly become stale. Aside from the unpleasant smell in the tank, your betta will also get sick.

4. It helps reduce the frequency of tank water changes

You don’t need to perform as many water changes if you have a filter in your betta’s tank. Water changes are essential to reduce harmful bacteria in the tank, but a filter does this too. 

In a filtered tank, you will only need to perform 15-25% water changes at least once weekly.

Without a filter, you would have to carry out more frequent water changes, especially if it’s a tank larger than 5 gallons. 

You can’t escape water changes because they are necessary so your betta fish doesn’t suffer. 

What Kind of Filtration Do Bettas Need? 

There are three types of filtration that most filters come with to keep the water clean for your freshwater companions. These include mechanical filtration, biological filtration, and chemical filtration.

Mechanical Filtration

Any filter you choose must be able to carry out mechanical filtration in the betta’s tank. The machinery in a mechanical filtration unit helps remove most of the solid particles and other visible debris so that the water is clean. 

But it doesn’t mean that all the harmful chemicals and dirt have been sufficiently removed from the water. That’s why other filtration methods are required.

You must remove and replace the mechanical filtration cartridge for steady water flow in the fish tank. If you notice a decrease in the water flow, it’s likely due to the high volume of water being blocked by the cartridges filled with debris.

To prevent debris this build-up up, replace the mechanical filtration cartridge every two to four weeks.

Biological Filtration

Biological filtration is essential for any betta fish tank. It helps clean the tank water without destroying the helpful bacteria responsible for breaking down harmful chemicals like ammonia.

Get a biological sponge filter with a large surface area because it can collect more bacteria. The biological sponge filter should also be exposed to air because helpful bacteria that grow around the filter need oxygen.

Chemical Filtration

If you’re worried about filtering out harmful chemicals from betta fish tank water, you should ensure the filter you get can perform chemical filtration.

Most chemical filtration is done using activated charcoal (heated charcoal). Activated charcoal is widely used because it can absorb most harmful chemicals from the water. 

You can also use other chemical media to remove ammonia and chlorine from the water. The chemical media needs to be changed frequently to function well. You can learn more about the best water for betta fish here.

Types of Filters to Consider 

As you’ve noticed, filters are essential for your betta tank. But there are various filters on the market, and you need to know which one you’re getting for your betta tank. 

Power Filters

You are more likely to find other fishkeepers recommending a power filter because they’re great for beginners and all three types of filtration to meet your fish’s needs.

Most aquarists place their power filters at the back of the aquarium. It comes with three types of filtration and a siphon to suck the water into the filter when needed. 

fish tank power filter

The water flowing through the media is cleaned and pumped back into the tank. Unfortunately, one of the downsides of using a power filter is that it has cartridges that need regular cleaning and changing. Not washing it will cause debris build-up, affecting the tank’s water quality. 

Powe filters are sometimes too strong for betta fish. If the filter moves your betta around too much, it’s too strong. Bettas have long fins, which don’t do well with strong currents. The stress can weaken your betta and make them sick

Internal Filters 

As the name suggests, internal filters are found inside the fish tank. Where you will place it depends on how you want to decorate the tank, but you can either use a suction cup to mount the filter on the wall or just put it across the tank’s substrate. 

Most internal filters need to be connected to a pump. It will pump air through the cartridges so that clean water can be released at the top of the filter. The two types of internal filters are corner or sponge filters.

Corner Filter

Filters are pretty straightforward to use, so with a corner filter, you should place it at the bottom corner of your fish tank. Corner filters can do all three types of filtration, but with the small amount of water passing through it, it isn’t the best choice compared to other filters on this list. 

Sponge Filter

If you’ve been researching filters, you’ll realize that the sponge filter is a favorite amongst betta fish keepers. If you’re only housing one betta fish, especially in a small tank, then a sponge filter will be perfect. 

To clean this filter, you should use aquarium waters so that you don’t destroy any beneficial bacteria while getting rid of debris.

betta tank sponge filter

Sponge filters are great, but they only carry out biological and mechanical filtration because of the sponge material. If you want to carry out chemical filtration, you will need to add another media to your filter.

This filter is excellent for quarantine and breeding tanks because it doesn’t carry out chemical filtration. Chemical filtration isn’t good for a quarantine tank with a sick betta because it can filter out the medicine, tampering with your efforts to help your betta fish recover. 

The water flow is also moderate, so you don’t have to worry about fry betta fish in a breeding tank. 

Undergravel Filter 

An under gravel filter is placed beneath the gravel in a fish tank. If you’re more concerned about your home aquarium’s aesthetics, this is an excellent choice because you can hardly see it from the outside.

betta tank undergravel filter

This filter has several tubes facing the surface of the water. When you place a power head on top of the tubes, the water is immediately sucked towards the gravel. So the dirt and debris will get stuck on the gravel, making it easy to remove.  

Unfortunately, under gravel filters aren’t entirely reliable. They work well but can also be a breeding ground for debris if not cleaned properly. It can affect your betta fish health.

These filters are not the best if you have plants in your fish tank. Having to clean the gravel due to this filter can affect any live plants in your fish tank.

It might be discreet, but is this filter worth all the work?

Canister Filter 

Canister filters are excellent for fishkeepers with larger tanks that house more than one fish species. You should use a canister filter if your betta lives in a tank with other fish.

This filter works by moving water from the tank to an external filter. The canister filter has high pressure that moves the water through the media and pumps clean water back into the fish tank.

Most aquarists like this filter because it’s powerful and effective at its job. Although you’ll need to frequently clean it because of its numerous parts, it’s one of the best filters on this list to try.

What To Look For When Buying a Filter For a Betta’s Fish Tank 

Getting a filter for your betta tank is crucial, but you must know which one to choose. Here is what to consider when selecting a good filter: 

The kind of filtration it offers

There are three types of filtration: mechanical biological, and chemical filtration. Most fishkeepers will be satisfied with a filter that can perform mechanical and biological filtration, but that’s not enough.

It’s best to get a filter that can fulfill all three because you never know what chemicals are lurking in the water. Having a filter that can perform all three also reduces the risk of your betta fish getting sick.

The tank’s water quantity 

The right filter depends on how much water you keep your betta in. Are they in a 5 gallon, 10 gallon, or 20 gallon tank? Most filters aren’t small and take up a lot of space inside the tank, so you must choose one according to your space.  

If you’re keeping them in a 5-gallon tank, you might have to consider filters that can be placed outside the aquarium so that you don’t take up any of your betta’s swimming space. The best betta tank for one betta is a 10 gallon tank. More bettas will need a larger tank and filter.

For example, a power filter in a betta tank with 10 gallons of water or less will be too stressful for your betta fish because of the strong currents.

The number of fish in the tank

The good thing about having a filter is you can keep more fish in your tank. While bettas can survive without a filter, other fish cannot. So if you want to add more tank mates, you can use a canister filter. It’s powerful, making it suitable for community tanks.

Cleaning and maintenance

While filters are necessary to keep the tank’s water clean, they also require cleaning and maintenance. All you have to do for some filters is wash the filter media with aquarium water. Other filters may require intense scrubbing and cleaning to remove the debris around them.

You should be able to remove and clean the filter media quickly. Taking too long will stress your betta fish, and we don’t want that. 

If you’re worried about giving your betta fish the best care, you can check out this betta fish care guide article for more information.

Why You Should Use An Aquarium Filter

While not all fishkeepers are excited about using filters in their tank, your betta needs it. Some filters look unpleasant when placed next to other tank decorations, but they will help your betta. 

Without one, it will be challenging to maintain the proper water parameters needed for bettas. Even with constant water changes, you can’t completely keep the water clean while that ensuring healthy bacteria thrive. 

They also reduce the work you have to do to care for your betta. If you don’t want to reduce your betta fish’s lifespan, you should keep a filter in the tank. 


Are filters good for bettas?

Yes. An aquarium filter is suitable for a betta’s fish tank to help oxygenate the water and remove dirt and harmful bacteria from the tank.

How long can a betta fish live without a filter?

Without a filter, a betta can live for probably a week excluding water changes. The toxic chemicals and waste that build up in a betta tank can be poisonous and affect your fish’s health. While they can live longer than this, it doesn’t mean they will be happy or healthy.

Do Betta Fish Need a Filter? 

By now, you know a betta fish tank with a filter will give your fish a better life than in a tank without. Tanks with filters are generally easier to take care for than without. Filters help clean the water, oxygenate the tank, and ensure beneficial bacteria grow to promote your betta’s good health. 

A reliable and efficient filter is vital to ensure your betta is healthy. 

You’ll also get a break from tediously changing the tank’s water, and your betta will like this because they don’t like the destabilization caused by frequent changes. 

So, which filters are you getting for your betta fish?

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