Do Betta Fish Tanks Need Filters for Clean Water?

do betta fish need filters
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Yes, betta fish will need a filter in the aquarium. While a betta fish can live in pretty much any fish tank, the best home for them would be a fish tank with a filter. This is important for a betta fish because it helps keep the water clean. 

What Do Aquarium Filters Do?

A filter is a device that removes pollutants from the water in your fish tank. This can include ammonia from your fish’s waste, decaying plants, and other contaminants that you may not be aware of. All aquarium filtration systems work similarly by using a pump to move water through an aquarium media like charcoal or filter floss where impurities are trapped. 

Filtration is one of the most important things to get right when maintaining your water quality. If you neglect them, you may find that your fish are attacked by parasites, succumb to diseases, and ultimately perish – no matter how well you care for them otherwise.

Not only do they provide mechanical filtration that traps dirt that keeps the water clear, but they also come with a range of benefits for your betta tanks that you might not know about.

Benefits of Betta Tanks with Filters

Remove Harmful Substances via the Nitrogen Cycle

Good aquariums are not necessarily filled to the brim with fish, plants, and other fun stuff like ornaments. Just like all animals, betta fish will produce fish waste. Sometimes, uneaten food might get stuck in between decorations that decompose and turn into harmful substances such as ammonia and nitrites. 

Great aquariums are home to beneficial bacteria that assist with the breakdown of these substances. This is a process called the nitrogen cycle and occurs in your filter through “biological filtration”. If these harmful substances remain in your aquarium, your fish will slowly suffer to death without you knowing.

Think of these bacteria and the nitrogen cycle like miniature garbage disposals that eat up the wastes like ammonia and nitrites in the aquarium and turn it into harmless substances like nitrates. Nitrate levels are only toxic after they reach a certain level (>20ppm) and can be removed through frequent water changes or the use of real plants.

Back to biological filtration, beneficial bacteria can be found on the surfaces of live rock, gravel, sand, aquatic plants, and even the glass of the aquarium itself.

Having a filter with good aquarium media will house most of your beneficial bacteria to make your aquarium habitable for your betta fish. 

Provides Water Movement for Mechanical Filtration 

The amount of moving water has in an aquarium is such a small detail, but it can have a considerable impact on water quality. Firstly, water movement allows for gaseous exchange that will oxygenate your fish tank. 

Although betta fish gets their oxygen by breathing air, this oxygen is essential for beneficial bacterial growth in your aquarium. I mean… living things do need oxygen to live! 

Water movement also plays a crucial factor in moving waste products from one place to another, which is vital to keep the tank clean. Without a filter, fish waste and food waste will just sit on the surface of your aquarium decorations which can be unsightly. A good filter will suck this waste up where your beneficial bacteria will break them down in the filter.

If you have plants in the aquarium, water movement is necessary to distribute all the nutrients around the tank as well!

Lesser Water Changes

With beneficial breaking down all the harmful substances, you can go longer periods without performing water changes. This is because your water quality will be significantly better. Without a filter, these substances build up quickly, and you’ll have to do water changes every few days.

But Betta Fish Habitats Don’t Have Filters!

All fish habitats don’t have filters, even betta fishes. Does that mean you shouldn’t put filters for other fishes you keep to? No.

In a betta fish habitat, depending on what type of betta fish you’re keeping, they either live in puddles or fast-flowing streams. 

Both habitats are surrounded by vegetation and large volumes of water that your aquarium is unlikely to replicate. Plants absorb the harmful ammonia, nitrite, and nitrates, while large water volumes dilute the toxicity. 

So unless you’re keeping your betta fish in a huge tank with loads of plants, you should get a filter.

However, when considering filters, the main thing you should take note of is…

Is Your Betta’s Filter Too Strong?

Many aquarium blogs mention that you should consider your aquarium size, how many gallons or litres of water, and multiply it by 5-10 times the volume. However, betta tanks don’t really need to follow this guideline.

The beautiful betta fish that you find in typical aquarium stores, for example, is native to the slow-moving waters of rice paddies and rain-fed ponds in Thailand (they’re actually not, but their wild versions do).

Because of this, they’re accustomed to much gentler water currents, if any. In fact, most bubblenesting bettas come from such habitats. So if you have a bubblenesting betta, a low flow is enough just to provide some movement. A good indicator is for you to check to see if they have difficulties swimming in the fish tank. 

Keep your filter to a low flow and places with still water for them to rest. Honestly, simple sponge filters, internal filters, or a small hang-on back will suffice to provide clean water. If you’re planning to breed them, make sure to have areas at the water surface that are still for them to build their nest.

If you’re keeping mouthbrooding bettas, they come from slow to fast-moving streams. Thus, it’s natural to have water flow in the aquarium. You can opt for a slow to medium flow using power filters or bigger hang-on backs to replicate this. Make sure to check on them constantly to ensure that they’re not struggling.

I like external hang-on back filters in my betta fish tanks to provide basic filtration for clean water. I will usually use a biological filter in my breeding tanks, such as sponge filters with an air pump or a small internal filter to keep the nitrogen cycle going and all the bettas happy.


After reading this, I hope that it has provided you with a better understanding of whether you should get a filter for your betta tank. Keep your aquarium water clean, and your betta fish will reward you with a longer life, and they might even breed for you!

If you’re interested in reducing the water changes for your betta tanks, you can consider a creating a riparium or a walstad method tank instead!

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