Do Betta Fish Need a Filter?

Do Betta fish need a filter?

This is a loaded question and depending on who you ask, the answer may vary. 

It’s difficult to “fight” against pet retailers (who are supposed to be experts in animal care) when they have uninformed workers telling customers that this species is “just fine” in a small bowl or vase, then proceed to sell them an inferior vessel to house their poor new pet in – the lucky Bettas may survive this ordeal for a while, but they will not live “happily ever after.”

We strongly believe that Betta fish do need a filter and we will explain the what for’s and whys throughout this post.

fish tank filter


Betta Fish in the Wild

We can’t completely blame pet retailers for allowing their customers to place the Betta in a tiny compartment. After all, even the most novice aquarists have probably heard that the Betta fish does live in shallow rice paddies and ponds in their natural habitat. Some may even endure droughts where their environment gets very murky, and warm with little water available to move about.

The survival of this species is made available throughout their natural world because they possess a “labyrinth organ.” This specialized “breathing apparatus” is located just in front of their gills. You can’t see it, but it’s there, working to allow the Betta to gulp oxygen from the atmosphere.

It’s because of this ability to survive in less water that has made the Betta sought after by beginners and those folks that do not want to deal with a large aquarium set up in their home. However, there is no shortage of myths circulating about the Betta which include how they prefer a cramped space and that they can survive purely on the roots of plants in a vase. 

NOT TRUE! And just plain WRONG!

Betta Fish Habitats Without Filters – What to Expect

If you have your Betta fish in a bowl or an aquarium 2.5-gallons (or less) a filter is not a practical addition. It is simply too small a space to accommodate even the tiniest of filters, and, in the long run, may do more harm than good by creating a strong current that pushes and pulls the Betta around. 

Bettas prefer slow-moving water and will become stressed out from constantly fighting a strong current. 

However, in a small container without a filter, you can expect the water quality to quickly decline. Leftover fish food and fish waste will cause a buildup of ammonia, nitrates, and nitrites. In a small unfiltered aquarium or bowl, these can cause stress and illness in your Betta (the most common being fin and tail rot). 

What if I constantly change the water?

Yes, water changes will help control the toxins from building up, but you are also breaking the biological (beneficial) bacteria from being able to take “root” which will also stress out your Betta. Not to mention the constant fluctuations in water temperature which can also lead to sickness and stress. 

Caring for a tiny, unfiltered Betta setup is a lot more work than investing in a suitable tank (at least 5-gallons) with all the right equipment (filter, heater, light). 

Betta Fish Habitats With a Filter

Imagine living in a cramped room that is slowly filling with smoke. Eventually, that smoke will get so thick you won’t be able to breathe well. Once a week someone comes and opens the door and window and clears out the toxins, but once you’re shut back in, it quickly builds up again.

That’s life for your Betta in an unfiltered tank!

Using this same analogy, now imagine someone places an air purifier in that room, even though the smoke may be coming in, that little unit is helping to clear it out, making the cramped space liveable. 

By adding a filter to your Betta tank you are not only taking out those excessive pollutants (ammonia, nitrates, nitrites) but you are also adding oxygen to the water which helps your Betta breathe easier and encourages him to be more active.

Benefits of a Filter at a Glance

  • Removes access waste and ammonia
  • Raises the oxygen level
  • Beneficial bacteria can grow in the filter media
  • May add tankmates in larger tanks
  • Reduces the amount of maintenance required
  • Helps control the temperature without hot or cold spots

We already know that an unfiltered container will require you to do partial water changes every couple of days and a complete change about once a week. However, in a filtered 5-plus gallon tank, you only need to do a 20 – 30 percent water change once a week and a complete change every 4 to 6 weeks. Fewer “overhauls” on a tank allow the beneficial bacteria to establish itself which helps your Betta maintain good health. 

Is Your Filter Too Powerful?

Now that we’ve convinced you that having a filter is a must-do in the Betta tank, you may think “bigger is better.” 

In some fish tanks, like Goldfish that put out a lot of waste, this isn’t a bad idea; however, our slow-moving Betta buddy will not appreciate the extra flow of that monster filter. In fact, filters that are too powerful can suck in those delicate fins of the Betta male. It will also cause him to hide or avoid that side of the tank for fear of being buffeted around or dragged into the intake. 

Signs Your Filter is Too Strong

  • Betta struggles to get to surface
  • Scared
  • Hides a lot
  • Frantically swimming in the filter’s current

Powerful filters can quickly exhaust a Betta, which may cause him to stop battling against the current allowing him to get buffeted in the flow or sucked into the intake. Both of these scenarios can mean injury or even death to your fish. 

What can I do?

  1. Check your filter to see if you can turn the flow down. 
  2. Place a pre-filter sponge on the intake to help slow it down
  3. Create a barrier between the intake with plants or decorations
  4. Replace the filter with a suitable model

Choosing the Right Filter

We highly recommend placing a Betta in a suitable aquarium (at least 5-gallons) that comes equipped with the right filter. However, if you just bought a tank without a filter or need to replace an old one, there are a few great choices on the market.

The Sponge Filter

One of the best options for small Betta tanks is the sponge filter. This unit consists of a large sponge over a tube with an air pump that draws water through the sponge. It does not create a lot of suction inside the tank, so your Betta won’t be battling against it, but it does still allow for both biological and mechanical filtration processes. The sponge filter will also oxygenate the water and is easy to set up. We recommend this type of filter for 10-gallons and under. 

Hanging Filter

This type of filter hangs on the back of your tank with a small intake tube and a waterfall effect output. These work well in 5 to 10-gallon aquariums and some do have an adjustable flow rate. If you feel the intake is too powerful for your Betta, you can easily add a pre-filter sponge to the intake. These filters are easy to maintain (just change the carbon inserts) and they don’t take up a lot of tank space since the bulk of the unit is outside the aquarium. 

Submersible Filter

These filters come in all sizes, but they can be tricky in smaller tanks as they will take up space and can be quite powerful. They do a great job in keeping the tank clean; however, there isn’t much you can do if they are too powerful with the intake and output, except loading the decorations around them which will reduce its effectiveness. We only recommend this type of filter if your tank is large enough to sustain one without being harmful to your Betta (over 10-gallons).

Do Betta Fish Need a Filter Conclusion 

Don’t be fooled by myths and misinformation. Even though Betta fish do live in slow-moving, shallow, murky waters in their natural habitat, these fish have been raised in those conditions and therefore know how to handle them. 

Domesticated Bettas cannot and should not have to endure poor water conditions in an environment they cannot escape from – remember, wild Bettas will also jump from one paddy or puddle to the next in search of better water. 

To keep a Betta healthy and happy you will need at least a 5-gallon tank equipped with a low/slow-flow filter that will keep the toxins under control, add oxygen to the habitat, and allow beneficial bacteria to grow. 

If your filter is too powerful, turn the flow down, add a pre-filter sponge to the intake, or add some decorations around it. However, this may not be enough, so watch out for signs of struggle and stress on your fish. If this is happening, replace the filter with a more suitable sponge or hanging model.