Do Betta Fish Need a Heater and Filter in their Tank?

A Nano filter like the AZOO Mignon might be perfect for your Betta fish's tank.
A Nano filter like the AZOO Mignon might be perfect for your Betta fish's tank.

Betta Fish Requirements

Betta fish are often housed in bowls. That means no filter, and no heater. Even people who keep Betta fish in small tanks rarely provide filtration or heated water, and they survive for the most part.

Really, this is what makes the Betta so popular. For beginning fish keepers, kids, college students and others who don't feel like dealing with the maintenance requirements of a real aquarium, the Betta is a way to have a pet fish without all the hassles of having a pet fish.

Unfortunately, these same Betta owners later end up wondering why their fish appears perpetually stressed, or suffers from some malady such as fin rot. Betta may survive in bowls of stagnant water, but that doesn't mean they are thriving.

Cold temperatures and dirty water can cause stress for your Betta and make him more likely to get sick and die before his time. But this doesn't mean you can't keep your Betta in an unfiltered, unheated tank. It just means you need to fully understand the requirements of your Betta fish before deciding if that is the correct decision. It also means you need to be ready to do the extra work required to keep an unheated, unfiltered setup in top condition for your fish.

In this article we'll take a look at whether or not you should consider housing your Betta in a tank with a heater and filter. If you are new to Betta keeping, you might want to first check out my article on proper Betta care:

How is the Betta Different from Other Fish?

What makes us think it's okay to keep a Betta in a bowl, anyway? We'd never consider putting any other tropical fish in a tiny bowl without a filter.

Betta fish do have physiologies that allow them to survive in low-oxygen environments in the wild. They are anabantids, or labyrinth fish, and they can come to the surface to take a gulp of air when they need it.

By the way, this is just one more reason keeping a Betta in a plant vase is a really stupid idea. Your Betta fish needs access to the water surface!

In the wilds of Southeast Asia Betta can live for short periods in small puddles where other fish would perish. This is because of evolutionary adaptations that allow the species to persevere in times of drought or poor water conditions.

In other words, they have evolved to take in air, not just rely on the oxygen in the water, so they can survive harsh conditions.

This makes them the perfect fish to house in a small bowl, or so it seems. They can do without the aeration effect of a filter, and survive even if the water gets dirty.

But think of it like this: You could probably go a month without food if you had to, living on the stored fat in your body. As humans, we have evolved to survive periods of famine by storing fat.

But how much fun would you be having during that month without food? You'd probably be pretty miserable, and you might even suffer from some physical problems as a result of your fast. Just because you are surviving doesn't mean you are thriving.

Does a Betta Need a Filter?

You can keep a Betta in a bowl, though I personally really hate seeing it. You need to really stay on top of weekly water changes, be sure not to overfeed, and keep the water crystal clear. You also need to make sure your room temperature remains appropriate for tropical fish, which means in the mid-70s.

When things go bad in a small bowl, they go bad really fast. Poor water conditions can lead to fin deterioration, infections and, ultimately, premature death for your Betta. This is why, if you are on the fence between a tank or a bowl, I strongly encourage you to choose the tank.

To thrive, Betta need clean water just like any other fish. Fish tanks with filtration are able to establish themselves as tiny ecosystems, although they're ecosystems that need a little help from you.

Does your Betta require a heater and filter in his tank?
Does your Betta require a heater and filter in his tank? | Source

Colonies of microorganisms develop in the tank and in the filter, and they assist in breaking down the waste caused by the fish and his uneaten food.

You don't need to, and shouldn't, do a complete water change in a tank with a filter as you'll destroy those helpful microorganisms. About 30% weekly water change is enough, plus vacuuming the gravel and cleaning up any algae.

This equates to about ten minutes of work per week for a 10-gallon tank. Compare that to the hassle and time involved with removing your Betta from his bowl or tank, completely cleaning it and the decorations, then adding clean water and waiting for it to return to room temperature before you can put Betta back in his home.

Tanks with filtration are simply easier to care for. And the larger the tank, the easier it is to maintain the system. A 55-gallon tank is much, much easier to maintain than a 1-gallon tank.

That's not to say your Betta needs a 55-gallon tank of course, but a 5-10 gallon tank isn't a bad idea.

The actions of a filter also help to oxygenate the water. Betta do best with low-flow filtration, as they tend to get knocked around a lot by high-output filters. Even a low-flow filter will help with oxygenation.

Below are a couple of filters to consider for your Betta. No matter what you choose, keep an eye on your fish at first and make sure he is coping with the water movement without any problems. If you need more information on finding an appropriate tank for your Betta, check out:

Azoo Mignon Filter 60

This is an inexpensive nano filter for small tanks up to 10 gallons. There are a few things I like about it.

The first is the adjustable flow rate. As stated before, Betta don't do well with fast-moving currents. They tend to get pushed around the tank, and that, of course, causes stress.

With this filter you can position it and adjust the flow so your Betta isn't struggling.

I like that it's a hang-on-back filter. Many nano filters are fully submersible, and they take up a lot of space in the tank. If you're already starting with a small tank, you don't want to cut down your Betta's swimming area even more with a bulky filter. With the Azoo Mignon, only the intake submerges.

Finally, I like that you can add your own filter media. Some filters are cartridge-based, and when the cartridge gets dirty you have to replace it with the exact same type of cartridge. With this filter, you can use whatever fits. You might just want to use a sponge to catch debris, or you may want to include something like activated carbon.

Rio Mini 90 Internal Power Filter

Here's another good choice for small tanks. It an internal filter, so it will take up a little space and attaches to the inside of the tank by suction cups. But it's a fairly small design that can be placed vertically or horizontally, so you can tuck it out of the way.

The output can be adjusted by the various included adapters, as well as the direction of the water output, to help keep Betta stress-free.

Like the Azoo above, you have the choice of different filter media.

This little filter would be a great upgrade for one of those aquarium kits that comes with the 1, 2, or 3- gallon tank plus the hood and the air-pump filter. People love those tanks for Betta fish, but they have their drawbacks.

Those air-pump filters are designed to be a type of under-gravel filter, and frankly they don't work very well. Even if debris gets sucked down into the gravel, there it stays to foul the water. It's far better to have a filter with a removable sponge so you can clean out any debris.

Does a Betta Need a Heater?

When people keep Betta fish in bowls or small tanks they usually don't consider a heater. This means the water temperature will be governed by the surrounding air temperature.

This can be bad news. Though people don't often think of them this way, Betta are tropical fish. That means they live in warmer water in the wild. They require temperatures from the mid-70s, up to around 80 degrees.

TOOGOO Digital LCD Fish Aquarium Marine Vivarium Thermometer -50¡ãC to 70 ¡ãC
TOOGOO Digital LCD Fish Aquarium Marine Vivarium Thermometer -50¡ãC to 70 ¡ãC

Monitor your water temperature so you know what impact your heater is having on your Betta, or if you even need a heater at all.


If your room temperature is consistently in the mid-70s at the lowest, you can get by without a heater. This is true of any tropical fish tank. But if you have periods, at night for instance, when room temperature drops into the 60s or even 50s, you need to consider a heater for your Betta's tank.

Just like pollution, water temperature is easier to control in larger volumes of water. The water temperature in a 1-3 gallon tank or bowl will drop fast as the air temperature goes down.

A 10-gallon tank will take a little longer to adjust, and big tanks even longer still.

Low water temperatures will cause stress for your Betta, and make him more at risk of disease and premature death. Remember, just because he's surviving doesn't mean he's thriving. You need to keep your Betta's water temperature between 75-80 degrees if you want him to be as healthy as possible.

One of the problems with very small tanks is that even very small heaters may heat them up too much, and you could end up killing your Betta.

This is all the more reason you should consider a tank 5 gallons or bigger for your Betta fish.

You need to monitor the water temperature and make adjustments to the heater size and/or settings as you go. Ideally, you should set up the tank, heater included, before you ever add your Betta to make sure the temperature is staying within desirable ranges.

Hydor 25W Submersible Glass Aquarium Heater - Original Theo
Hydor 25W Submersible Glass Aquarium Heater - Original Theo

This heater is a popular choice for a 5-gallon tank. Make sure you monitor your tank temperature closely to ensure it's working okay for you! Ideally, you want to test the heater out in the tank before you add your fish.


Taking Care of Your Betta Fish

Although I'd really like to see you choose a larger tank with filtration and a heater for your Betta, you can keep him in a bowl if you stay on top of weekly water changes and make sure the water temperature is appropriate for his needs.

The Rio Mini Power Filter has an adjustable output,making life easier for Betta.
The Rio Mini Power Filter has an adjustable output,making life easier for Betta.

Missing a water change, or two, or three, will soon mean doom for your pet fish.

If you are too busy to perform the weekly maintenance on a smaller vessel, consider keeping your Betta in a 5 or 10-gallon tank with a heater and filtration. It's less work for you, and a better environment for him.

Betta fish are truly the most abused aquarium fish in the world, by both their well-meaning but uneducated owners and by an industry that pushes them out by the millions as disposable pets. It's unfortunate, but countless Bettas are purchased every day by people who have no clue about their needs.

It's all about education. The first part is understanding how to care for your Betta fish correctly. The second part is telling someone else, so more of these fish can thrive instead of just survive.

Please consider keeping your Betta fish in at least a 5-gallon tank with the proper filtration and heater.

Your Betta Tank

What size tank will you keep your Betta in?

  • 1-gallon tank or bowl
  • 2-gallon tank
  • 3-gallon tank
  • 5-gallon tank
  • 10-gallon tank
See results without voting

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Comments 21 comments

janderson99 profile image

janderson99 2 years ago from Australia on Planet Water

Very interesting. Thanks!

sheilamyers 2 years ago

If I ever got a Beta, I'd buy at least a two gallon aquarium and have both a filter and heater. I like what you said about even if a person's house stays around 70 degrees, it can get colder at night. As hot and humid as it gets at my place during the summer, there are times it gets cool enough at night that when I get to my living room in the morning the heater in my 28 gallon tank is on (I have it set for 75). And some people tend to forget the water in a small bowl or tank can chill quite rapidly if the air conditioner is running, especially if the bowl is near a vent.

EricDockett profile image

EricDockett 2 years ago from USA Author

Thanks janderson99!

Two-gallon isn't bad Sheila. 5-gallon is better! :-) But 2-gallon with a filter and heater is definitely much, much better than a bowl.

mariekbloch profile image

mariekbloch 2 years ago

Completely agree with this article. I have three bettas. One is housed in a 5.5 gallon, and the other two share a divided 20 gallon long, so that's 10 gallons each. They are beautiful fish that need to be treated like fish, not d├ęcor.

EricDockett profile image

EricDockett 2 years ago from USA Author

Thanks mariekbloch. Sounds like you have some nice setups for your Bettas!

Isabella 10 months ago

My male Tetra Betta was starting out well then something happened to his lip it looks like it got hurt but wht could it have gotten hurt on? Hes becoming really "lazy" he doesnt swim around like he usually does... i dont have a heater or a filter but i clean his tank almost every sunday and i fill it with distilled water i make sure his tank is super clean and i feed him with TetraBetta food literally thats the name TetraBetta its pellets he hasnt been eating them right away well he trys to but he struggles and honestly hes been alive for awhile with this whole lip problem but i still cant figure out whats wrong with him i really need help please...

EricDockett profile image

EricDockett 10 months ago from USA Author

Hi Isabella. It's tough to guess about the lip thing. A few thoughts:

-Try him on a feed/fast schedule for a week or so.

-Make sure the water temp is appropriate. Should be 75-80 degrees as any tropical fish.

-Lightly dose his tank with freshwater aquarium salt (NOT marine salt) in case there is an infection brewing. Discontinue the salt if his condition improves.

-Don't use distilled water. Many of the minerals are removed. Switch to quality spring water.

I'd try those options before anything else. If you can identify it as a fungal or bacterial infection you'd have more precise options. Good luck!

VexiWolf 9 months ago

Hi there,

I just got my half-moon double tail betta a couple of days ago. I haven't had a fish since I was in grade school and I really wanted to give it a shot and do it right. I haven't bought a heater for my API 1.5 gallon tank and I know that the water is below the desired temperature. Is there a good heater that I can use to help get him through the winter months? I've been doing research like crazy but I haven't found anything.

Also the filter that came with the tank has a current that is way too strong, I can't change out the filter and I'm not exactly sure how to divert the flow so my betta can swim around more easily. He's been sitting at the bottom of the tank with stress lines running over his body.

The poor thing is so stressed out, I don't know what to do...

EricDockett profile image

EricDockett 9 months ago from USA Author

Hi VexiWolf. I don't feel all that confident recommending a heater for a 1.5 gallon tank. There are small heaters intended for bowls you may try. You need to be really careful it doesn't overheat the water, though.

If the filter current is stressing him out to the point where he won't even move, you may be better off without it. You can do a weekly water change for a small tank like that pretty easily, but make sure you stay on top of it. Otherwise, there are nano filters you can try, but again that's a very small volume of water.

Really, my advice is to get him into a bigger tank. You'll find more and better options for heat and filtration for 5 and 10-gallon tanks. It will be easier for you to maintain, and a better living situation for him.

It's up to you. Good luck, whatever you decide!

Betta newbie 8 months ago

Can I use this filter for a ten gallon??

EricDockett profile image

EricDockett 8 months ago from USA Author

Always check the manufacturer recommendations for tank sizes when it comes to heaters. It's smarter and safer than guessing. :-)

Kelsey 6 months ago

I feel so bad want to get a Heater but can afford it at the moment however I do have a filter a bubble maker set on low and everything else just for now don't have a heater and recommendations. I saved my beta from Walmart they way they treat their betas are horrid!!my room is extremely warm but I want to make sure my beta is as safe as possible

EricDockett profile image

EricDockett 6 months ago from USA Author

Hi Kelsey. If your room is around 75-80 degrees you don't need to worry about the heater.

Re: saving Bettas. You didn't do anything wrong, so please don't take this in a negative way. Just for future reference and for anyone else who reads this:

"Saving" a fish from a bad pet store seems nice, but in reality when we do that we are reinforcing the behavior of the store. Some stores have no business selling fish, and buying from them (as far as they are concerned) tells them we like their product, and are happy to buy them. They just see the numbers. They don't know why we did it.

If you don't like how a store manages their fish, you can talk to the manager. I actually did that once with a big store store like the one you mentioned, and they really did listen and make a change.

I hope your Betta lives a long life and you don't need to buy another for a very long time. But if and when you do, it always better to buy from and support a store that manages their stock in a more humane way.

Food for thought. Good luck with your Betta and let me know if I can help!

Brandon 2 months ago

I'm a college student and we are can't have very large tanks so my Betta is in a 1 gallon tank that National Geographic makes. He has an Amazon Sword plant, some blue gravel, and obviously water (treated with conditioner made by Aqueon). That's all that's in his tank, besides occasional food. I just got him yesterday from PetSmart. He seems happy enough, but it's like he goes on pause for a while sometimes and just freezes and floats. I just want to make sure he's OK, my thought is he's still just adjusting from his move.

EricDockett profile image

EricDockett 2 months ago from USA Author

Hi Brandon. If your Amazon Sword survives it is going to be busting out of that little 1-gallon tank. They are large plants that will easily grow to the top of a 75-gallon tank. I'd think about replacing the plant with a decoration your Betta can hide in. In a tank that small you're going to have to do full water changes and cleanings anyway, and that's going to make it tough for the plant and the fish. Up to you.

As for Betta, if you just got him yesterday it is certainly possible he is still adjusting to his new home. Don't interpret all weird behaviors as something wrong. Look for specific behaviors like glass surfing, or watch for his face and jaw turning gray or white. These are signs he is stressed.

Good luck with Betta! If your school allows 5-gallon tanks I seriously suggest upgrading him ASAP. 1-gallon is very small, even for a single Betta.

Julie 6 weeks ago

I think my betta has Finn rot. I have a 2.5 gallon tank with a filter but no heater. He is a little over a year old and has done fine up until now. I just did 100% water change which I don't like to do often and he really went down hill after that. What can I do to save him?? Please help. He's very tired and gets pulled around when the filter is on which never happened before so he hides in his house. Please help Sully!

EricDockett profile image

EricDockett 5 weeks ago from USA Author

Hi Julie. Fin rot is typically due to poor water conditions. Review your tank maintenance practices and see what you think might be wrong. Keep his tank water clean and clear, and if it is really bad you may dose with aquarium salt for a few days to prevent infection. Otherwise, it's just a matter of keeping the water clean and waiting for the fins to grow back. Good luck!

Amy 5 weeks ago

Hi, I have a new betta in a 5 gallon tank with a filter but no heater. He is in my classroom at school and the classroom stays around 78 degrees. It is a school building so stays fairly chilly. I have ordered a 25 watt heather for my tank (it will be here tomorrow).. But I was wondering if its safe for the fish to add the heater and slowly adjust the temperature? Or do I need to take him out?

EricDockett profile image

EricDockett 5 weeks ago from USA Author

Hi Amy! If the class room is around 78 degrees then the tank water should be around 78 degrees. That's a good temp, and the heater will keep it stable. No need to take him out. Just make sure you monitor the water temp so you know the heater is working properly. Good luck!

Kady 12 days ago

I have my crowntail male in a 5.5 gallon tank with a heater at 78 degrees Fahrenheit and a filter that he likes swimming with,because the current isn't too strong. Every month I change the filter cartridge and every 2 weeks I do a 50% water change. I even have a small bowl (2 gallons) to keep him in while I clean his tank.

He has a castle to hide in and 2 silk plants he likes resting on. I have gravel that I clean out on his tank floor. He's fed a rotating diet of flakes, pellets, and brine shrimp. I turn off his light at night and I turn off his filter while he's eating so it won't steal his food. I always make sure the water is conditioned and warm too.

he has a perfect life, but he seems so stressed out. His tail has lots of black dots on it, which weren't there before, and it looks like he's been chewing on it. I'm not sure if he's just lonely, but I don't have any room for tetras or snails in his tank. Any suggestions on what I can do to make him happy again?

EricDockett profile image

EricDockett 11 days ago from USA Author

Hi Kady. He is not lonely. Betta fish don't get lonely, and you're right: the tank is too small for any other fish. It sounds like he has fin rot, which is typically brought on by stress and/or poor water conditions.

I'm wondering if you are over-cleaning his tank and killing off the helpful bacteria that live in the gravel and the filter. I also wonder if you might be over-feeding a little. Perhaps try backing off on his feeding and giving him a fast day once a week. You can probably get a little more mileage out of those filter elements too. Healthy microbe colonies will develop on it and help keep the water clean. When you change it once a month they never have a chance to grow.

If possible, keep him in his tank while doing the water change. The stress of removing him is likely worse than what he'd experience if you kept him in there. You can vacuum the gravel with a small siphon and add warmish water back to the tank when you're done.

Good luck and let me know what happens!

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