What Is The Best Tank Size For Betta Fish?

Providing the right tank size is important to keep your betta happy and healthy. While some suggest a tank as small as 1 gallon, this may not be enough for your betta to thrive.

So, keep reading to learn the most important information regarding the size of your betta tank, and how you can make sure your betta is healthy and happy.

Key Takeaways:

  • The recommended minimum tank size for a betta fish is 5 gallons, but bigger tanks are considered better for their well-being.
  • Larger aquariums provide more stability, dilute harmful substances like ammonia, and require less frequent and intense water changes.
  • Bigger tanks allow for the possibility of housing more fish and reduce the likelihood of aggressive behavior in bettas.
  • Temperature fluctuations are less pronounced in larger tanks, providing a more stable environment for bettas.
  • The myth that fish grow to the size of their tank is debunked; while they won’t reach their maximum size in a small tank, it’s crucial to prioritize their happiness and well-being.

How Many Gallons Does A Betta Need?

Instead of thinking about it as what tank size is recommended, it’s better to think about the minimum size. Because the truth is, the bigger your tank, the better.

A betta fish needs a tank which is a minimum of 5 gallons in size, however bigger is going to be better. So if you are planning on getting the smallest tank possible while still keeping your betta happy stick to 5 gallons.

If you’re interested in upgrading your tank, then here are the Best 5 Gallon Tanks For Bettas.

Why Are Bigger Tank Sizes Better Than Smaller Tanks for Betta?

It seems contradictory to think that bigger tanks are better than smaller tanks. You may think they’re going to be more work to maintain. However, the bigger your tank the less work you’ll have to do. Here are a few reasons bigger tanks are better:

Large Aquariums Are More Stable

If you have a smaller aquarium then the bioload can build up a lot quicker than in larger aquariums. Once the bioload becomes too high, then there will also be a huge build up in ammonia. Ammonia is poisonous to bettas and if your tanks levels stay high for too long then your betta and any other fish will die.

When there is a larger amount of water in your tank ammonia and any other chemical will be more diluted. This means it’s going to take a lot longer for your tank to reach a dangerous build up.

As well as this you won’t need to perform water changes as often, or with as much intensity. In a smaller tank, you’ll have to change the majority of the water every week, whereas in a larger tank you can get away with changing the water less often.

The science has proved this as well. A study in 2015 by Arielle Dolan found that when you kept bettas in huge aquariums, some were even able to live for 7-8 years!

You Can Stock More Fish

Another problem with smaller tanks is that they can’t hold as much fish as larger tanks. For example, it won’t take much fish to overstock a 10-gallon tank, and you may not even realize you’re doing it.

However, you won’t have this problem in a bigger tank. The bigger your tank the more fish you can house safely. And while you may not want to have any other fish except your betta, later down the line you may change your mind.

The Temperature Doesn’t Fluctuate As Much

Another problem with smaller tanks is the temperature fluctuations. External temperature is going to affect a smaller tank a lot more dramatically than a larger tank. A sudden drop in temperature in your room is going to cause the temperature in a tank as small as 5 gallons to drop quickly. Even if it’s from leaving your window open.

However, a bigger tank is going to take a lot longer for its temperature to rise and fall. Because the fluctuation won’t be dramatic in a bigger tank your betta isn’t going to feel it as much.

Your Betta Isn’t Going To Be As Aggressive

The bigger the tank is the less likely your betta will be aggressive towards other fish. Because they’re going to have more space to call their own territory. Not only will you be able to house your betta easier, but you may be able to keep another semi-aggressive fish as well.

Such as Redtail Sharks, which need at least 55 gallons of water. In a tank this size, you won’t have to worry about them attacking each other.

Do Betta Fish Grow To The Size Of Their Tank?

It’s another common belief that fish will grow to the size of their tank. So if you had a 100-gallon tank then your betta would grow a lot bigger than a betta in a 1-gallon tank. While there is some truth in this, it’s mostly a myth. If a betta is in a tank that’s too small for them, they’ll never grow to their maximum size (which is generally 2.5 inches, however, some can grow to 3 inches as well).

But even though they won’t grow as big as they should, that doesn’t mean it’s okay to keep them in a smaller tank. They’ll be dreadfully unhappy. And the monotony and cramped space will stress them out. Eventually, their immune system will weaken and they’ll get sick.

So while bettas may not grow properly in a small tank, they will never get larger than around 3 inches.

Can A Tank Be Too Big For A Betta?

Luckily, you can have any size tank and your betta will be happy in it. The bigger the tank the more room there is for him to explore. However, what’s really important isn’t the size of the tank but what’s inside it.

Bettas are used to densely planted areas in the wild as well as a habitat with lots of places to hide. So if you have a large tank but no plants or ornaments then your betta will be stressed out. If you plan on having a large tank, then make sure you provide your betta with lots of hiding places. And to really make it feel like home add a lot of plants as well.

Anacharis, Hornwort, Anubias, Java Moss, and Java Fern are all great choices.

If you do plan on buying a large tank, you should try to avoid one that is too deep. Bettas have a labyrinth organ which means they need to go to the surface of the tank to breathe. If your tank is too deep, then it may have trouble reaching the top. While the chances of your betta dying because of this are incredibly low, it may stress him out a lot.

So as long as you keep your tank well decorated it will never be too big for bettas. Driftwood and large-leafed plants are all great choices. As well as using rocks and cave-like structures for your betta to hide in

If you’re interested in buying a 5-gallon tank then here are the best 5 gallon tanks for betta fish.

How To Calculate How Many Bettas You Can Keep

With bettas I don’t follow the 1 gallon per inch of fish rule. While this is a great rule for a lot of fish, bettas are too aggressive. Obviously for males you’re only keeping one per tank no matter the size.

For females, you’ll initially want 5 gallons for one, with an extra 3 gallons for any additional females you plan on adding. And always make sure you’re keeping them in odd numbers to reduce the chances of aggression.

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FAQ

Here are some more specific and frequently asked questions people have:

How Many Bettas In A 3 Gallon Tank?

Bettas should never be put in a 3 gallon tank. They are too small, and with the water fluctuations, not only will your betta have a shorter life, they’ll also have a much unhealthier life. Some other reasons not to put them in a 3 gallon tank include:

  • Reduced space prevents bettas from moving freely around the tank.
  • Added tank décor reduces water volume so that the fish have even less room.
  • Some 3-gallon aquariums don’t have enough surface water.

How Many Bettas In A 5 Gallon Tank?

Betta’s can live in a 5 gallon fish tank, however, this is the minimum size they can survive in. At this size you can keep 1 male or 1 female betta. Anymore than this, and the water conditions may deteriorate as well as aggression occurring.

Remember that setting up a tank includes adding extra equipment as well, so 5 gallons may become a bit smaller in practice. Everything you add reduces their swimming pace, including heaters and filters. With this in mind anything smaller would leave a betta with little or no space.

How Many Bettas Can You Put in a 10 Gallon Fish Tank?

A single male betta or 2-3 female bettas can live in a 10 gallon tank. You can also keep 2 males with a tank divider, however, I personally wouldn’t recommend it unless you can make sure they’re never going to see each other. Otherwise they’ll just spend all their time flaring.

So What Is The Best Tank Size For Betta Fish?

So as you can see when it comes to tank size bigger is better. If you’re short on space then you should try to avoid tanks below 5 gallons. And remember:

  • It may sound counterintuitive but bigger tanks are easier to maintain than smaller tanks. They take longer to become dirty, and when they do become dirty you won’t have to change as much of the water out.
  • While 2.5 gallons is commonly recommended, if you want your betta to have a happy life, then you should avoid a tank that small.
  • Some of the reasons bigger tanks are better than smaller tanks are that they are more stable, the temperature fluctuates less, your betta is less likely to be aggressive, and you can stock more fish.
  • If you put your betta in a tank that’s too small then he won’t grow to his full size. However, even in the biggest tank, they will not grow more than 3 inches in size.
  • A tank can never be too big for your betta. Just make sure that a large tank is planted and it’s not too deep.

If you’re interested in giving your betta the best life possible, then check out this article which talks about everything your betta fish needs! And now you know that the right size tank is going to affect your betta’s lifespan, here’s more information on how long bettas live as well as how you can prolong their life!

If you want to master the art of Betta fish care in no time, check out this article!

Tropical Fish A-Z
About the author

Hey! I'm Antonio!

Betta fish keeper for over 6 years now! Since owning a betta I've also housed all kinds of tropical fish, and have seen all manner of problems and how to look after them!

If you need any advice you can always message me or better yet join the Facebook group where a community can answer your questions!

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