Can Betta Fish Live Without a Filter?

-- By Carol

When keeping a Betta fish, it’s important to ensure that the setup of the tank is a replica of an underwater ecosystem.

This requires delicately balancing several elements to offer the perfect thriving environment.

Filtration forms a significant part of that delicate balance that helps everything thrive and grow.

Having said that, a filter is crucial for fish tanks.

Betta fish, however, can live without a filter if you make adjustments to the water often and monitor the nitrogen cycles.

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Can Betta Fish Live without a Filter?

Yes, a betta fish can live without a filter but that doesn’t mean that they’ll be completely fine.

Before you make sense of that, note that you’d hardly find a fish in nature that can survive for longer periods in water that has not been naturally filtered.

The underlying purpose of a filter is to keep the tank clean and replicate that natural setting.

Let’s find out what may happen to your betta fish if you don’t include a filter in the tank.

What Happens to Your Betta With No Filter in the Tank

Without a filter, countless harmful bacteria start reproducing in the fish tank.

Many harmful chemicals can stay in the tank and become more diluted as you change the water.

As long as they remain in the tank, they’ll remain a threat to your betta.

Plus, the dirty water itself can cause your betta to stress out, weakening its immune system and making it more vulnerable to diseases.

Water quality is greatly compromised in low-volume unfiltered tanks.

The smaller the volume, the faster the water quality will decline, and the more difficult it will be to maintain.

Feces and uneaten food results in the build-up of nitrate, nitrites, and ammonia. These substances, in large quantities, stress out betta and make them sick. That’s why tail and fin rot are common ailments in unfiltered tanks.

Hence, your Betta will be able to survive for some time.

Yet, it will experience a slight reduction in its lifespan, and that too if you ensure more frequent water changes than usual.

Changing water, again and again, can itself stress out your betta.

Also, the growth of beneficial bacteria is important to get control over water parameters. Changing water conditions makes your tank conditions unstable.

Not having a filter also means that the water in the tank will not be oxygenated, causing it to become stale.

Not only will this cause your betta to become sick, but it will also make your home smelly.

Making It Safe for Betta Fish to Live Without a Filter

The labyrinth organ in betta fish allows them to survive in small bowls.

This is because they can breathe atmospheric air. As a result, they do not need a filter in the aquarium to survive.

That said, they will die if you do not change the water frequently.

Change the Water in the Aquarium

You will need to partially change the water in the aquarium if you don’t use a filter.

Ammonia builds up rapidly if there is no filter in the aquarium. Your betta fish will eventually die if the ammonia build-up is not controlled.

Furthermore, the fungus and bacteria will kill your betta fish.

Partially Replace the Water Once or Twice a Week

Partially change the water in the aquarium by 20% to 35% once or twice every week.

Changing the water partially will ensure that the parameters stay consistent.

Make sure not to change the water completely. Doing so will shock or stress your betta fish, which can be catastrophic to their health.

You should also make sure that the new water temperature is the same as that in the aquarium. Temperature changes can stress your betta fish.

A partial water change is also the right step because it won’t remove beneficial bacteria from the aquarium water.

Good bacteria develop in aquarium water when there are betta fish in it. Thus, this bacteria will help betta fish stay healthy.

Therefore, regular partial water changes will help betta fish survive without a filter.

Why Filters are Important for Your Betta

Over time, the fish tank collects debris from various sources. This can include decaying matter, harmful bacteria, rotten food, chemicals, and feces.

For the well-being of your betta, all these harmful elements need to be removed from the tank from time to time.

A filter eliminates these harmful substances by sucking the water and passing it through a rigorous infiltration process.

After undergoing this process, the tank water becomes safe and clean for your betta. Let’s dig deeper into the reasons to use a filter in your betta tank.

No Need to Change Water Frequently

Water changes are necessary to remove harmful chemicals and bacteria from the tank.

As long as you have a filter in your betta tank, you won’t need to perform water changes frequently.

This is because the filter carries out this function too.

This, however, doesn’t mean that you simply stop changing the water altogether.

You still need to change water on your own because frequent water changes replenish the nutrients and minerals that your betta needs.

The minimum tank size for betta fish is 2.5 gallons, yet it’s best to use a 5-gallon tank or larger.

When keeping bettas in an unfiltered tank, you will need to change around 75% of the water every other day and ensure a full 100% water change each week.

On the other hand, in a filtered betta tank, a 100% water change is not required at all unless you’re faced with a rampant disease problem or algae.

You will only need to vacuum the gravel and conduct a 25% to 30% water cycle each week.

As per your filter’s instructions, you’ll need to replace your filter media too.

When it comes to cleaning the filter, use tank water instead of tap water so as to preserve beneficial bacteria.

Keeps Water Running

A filter also helps to move water around in the tank, which is extremely important for your betta.

Water that’s left to stand for prolonged periods starts absorbing carbon dioxide.

This not only proves dangerous for your betta but also impacts the pH levels in the betta tank.

While using an air stone should help you overcome this, why not simply use a filter to avoid facing the problem in the first place?

Eliminates Nitrates, Nitrites, and Ammonia

What proves most dangerous for your betta, however, is the buildup of nitrites, nitrates, and ammonia in the tank.

Excessive amounts of each of these, if not removed, can prove fatal for your betta.

For instance, too much ammonia can stress out your beta, thereby weakening its immune system.

Leaving ammonia in your tank for prolonged periods will eventually cause your betta to die.

Aquarium filters comprise sponges that harbor beneficial bacteria that feed on nitrites, nitrates, and ammonia. This helps maintain safe levels for the three harmful substances.

It’s true that beneficial bacteria are present in your tank, but it’s not usually enough to regulate the harmful bacteria.

A filter helps provide ample amounts of beneficial bacteria that keep growing over time.

Oxygenation of Tank

You now know that a filter helps move water around in the fish tank.

This, in turn, also oxygenates your tank. Since bettas contain a labyrinth organ that allows them to breathe from the water surface, oxygenation of the tank may not be necessary.

But because you’ll want to have plants and perhaps other types of fish that get along well with bettas, taking care of oxygenation is important.

How Strong Filter to Use with Betta?

While these were some of the reasons to have a filter in your betta tank, your filter shouldn’t be too strong.

For tanks under 3 gallons, any filter will prove too strong for your betta.

That’s why it’s strongly recommended that you upgrade your betta habitat to at least 5 gallons.

Internal filters and those hanging on the back come in varying strengths and are often too strong for bettas.

If your betta looks scared or is hiding, is not able to make it to the water surface for air, and is frantically swimming in the current, remove the filter or lower the strength of its current.

Not acting on time can cause severe stress to your betta and cause injuries such as fin damage, or even death.

Once they’re physically exhausted, they’ll be tossed around in the tank or maybe sucked by the intake tube of the filter.

Keep an eye on the water levels too. If the filter’s output reduces the tank water to below the recommended depth, water conditions will become unstable.

If the filter in your betta tank looks too strong, set the lowest setting for the flow of the filter.

If you have a non-adjustable filter, consider replacing it with an adjustable one. If you don’t wish to replace it, follow these tips to limit the flow of the filter:

Increase the number of decorations or plants near the filter that will break the flow as it enters the tank.
Divide the tank to set up a separate compartment for filtration
Place a pre-filter sponge on the filter’s intake tube. This should restrict water uptake, which in turn, will limit the output. Pre-filter sponges should easily fit the output tubes of many filters. This way, you should be able to avoid turbulence and control the flow, creating a better environment for your betta fish.

Best Filter to Use for Betta Fish

Your tank size will determine the type of filter you should choose. If you have a small tank, a sponge filter is an ideal choice for you.

This filter draws water through a sponge using bubbles of air from an air pump.

Not only is it easy to set up but it also allows for biological and mechanical filtration. They also offer oxygenation and are perfect for the delicate betta.

They function best in aquariums up to 10 gallons and pose no threat to your betta from flow or suction.

Alternatively, you can choose the HOB (hanging on the back) nano filter. These are designed for 5 to 10-gallon tanks or larger.

Since they hang at the back, they don’t consume the ecosystem or viewing space.

Consider buying one that comes with an adjustable flow rate and place the pre-filter sponge on the intake tube.

Finally, you can also opt for an internal filtration unit that’s positioned inside the tank. They can be attached to the tank’s wall using suction cups.

However, these are not suitable for smaller tanks (3 gallons on smaller) as they can significantly reduce the water volume and swimming space for bettas.

Avoid Power Filters for Your Betta Fish Tank

Power filters are great for most types of aquariums.

However, they can be harmful to betta fish.

This is because they provide high current, making it difficult for your betta fish to swim.

Power filters are especially a bad idea if your betta fish aquarium only has 10 gallons or less of water.

How to Tell If the Filter Is Not Right for Betta Fish

The easiest way to discern if an aquarium filter is not right for betta fish is to pay close attention to the water current.

The water flow on your filter is too strong if:

Your betta fishes swim frantically against the water current
The fish seem to hide from the filter or stay away from it

You should change your filter if you observe any of the two situations above.

If you already have a water filter, you don’t necessarily have to purchase a new one. You can place a tank sponge on top of your filter’s intake part.

Closing Thoughts

To sum it up, bettas can certainly live without a filter but not for very long. Not including a filter makes your fish susceptible to sickness and diseases.

As a betta lover, you definitely won’t like that. When installing a betta filter, though, choose one that doesn’t prove too strong for the tank.

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