What Size Aquarium Is Best For Betta Fish?

A great concern when buying a betta fish is ensuring that you purchase the perfect tank to go along with it.

Many people suggest that bettas can survive in a one-gallon tank.

While this may be somewhat true, bettas won’t be able to survive for too long in such a small tank, let alone be happy!

What is the Minimum Aquarium Size For Betta Fish?

Betta fish prefer big tanks over small ones. The smallest tank size required to keep your betta fish happy and healthy is a five-gallon aquarium . Any tank smaller than this will not be good for your fish. For betta fish, always remember that the bigger the tank, the better it is!

A giant betta fish is at least twice the size of a normal betta fish. If you’re planning on hosting this fish, you will require a 10-gallon aquarium, at least.

While male bettas fail to live in groups due to their aggressiveness, female betta fish is quite the opposite. Female betta fish living together is called a sorority.

A 20-gallon aquarium, at least, is required to host a sorority of betta fish consisting of five females.

The Suggested Aquarium Size for Betta Fish

When you’re searching for the most appropriate and ideal-sized aquarium for your betta fish, you will come across a lot of opinions. You will mostly find people suggesting 2.5-gallon fish tanks.

Even though bettas can survive in a tank as small as 2.5 gallons, such an aquarium is not recommended. These beautiful creatures will be extremely unhappy in such a small tank.

Some people even suggest that bettas should be placed within a 1-gallon aquarium, which is highly unreasonable.

Related read: Do Betta Fish Get Lonely?

Why are Big Aquariums Better than Small Ones?

Many people think that bigger aquariums are harder to maintain than smaller ones. Well, that is not the case. The bigger your aquarium is, the less work you’ll have to do to maintain it.

There are a few reasons why bigger tanks are better for betta fish than small ones.

Big Fish Tanks are More Stable

Big aquariums don’t require as much maintenance as smaller ones. The bioload buildups a lot faster in small tanks than in large tanks.

Bioload buildup has significant implications on the fish tank, such as the release of ammonia.

Ammonia is a substance that is poisonous and hence, fatal to bettas. In case the ammonia levels of your tank remain high for too long, your betta fish along with any other fish will die.

Also Read: How to Get Rid of Ammonia and Nitrates in an Aquarium?

The bigger the tank, the more water there will be to dilute ammonia or any other chemical for that matter. This implies that it can take quite some time for your fish tank to reach a harmful level of ammonia build-up.

Bigger tanks also don’t require water changes as frequently as small aquariums do. A small tank requires a change of water almost every week while a big tank doesn’t.

Big Tanks Host More Fish

It’s obvious that large tanks can host a far greater amount of fish as compared to small tanks.

It’s important to know that it doesn’t take too many fish to overstock a tank. With a big tank, you won’t require you to worry about how many betta fish you can stock without killing or harming them in any way.

Big Tanks Have More Stable Aquarium Temperature

Small aquarium tanks experience multiple and more frequent temperature fluctuations.

The external temperature can affect the internal temperature of a smaller tank dramatically. A sudden drop in the surrounding temperature will also cause an immediate drop in the temperature of your 5-gallon tank.

It takes longer for bigger tanks to experience temperature fluctuations. This means bigger tanks offer more suitable temperatures and an overall environment for betta fish.

Your Betta Fish Won’t Be As Aggressive In Big Tanks

Betta fish require an ample amount of space for themselves in order to live and thrive peacefully.

They show aggressive behavior if they’re placed within a limited-space tank with too many fish. So, the bigger your aquarium is, the less likely your betta fish is to display aggressive behavior towards other tank inhabitants.

Since they’re territorial fish, they will have enough space to claim as their own territory in a bigger tank.

This will naturally reduce their chances of being aggressive towards others. This way, you will be able to house other fish in the aquarium as well.

Can Betta Fish Grow to the Size Of the Aquarium?

A common misconception is that fish grow to the size of the tank. This isn’t how things work. However, if you place a fish in a small tank, they may stop growing due to the unfavorable environment of the tank.

If you have a bigger tank, your betta fish will naturally grow better and healthier than they would in a smaller tank. Betta fish will never be able to grow to their maximum size, which is about 2.5 or 3 inches when placed in a small tank.

You need to understand that even though they might not grow as big as they should, it’s not appropriate to host them in a small aquarium.

Your betta fish will end up extremely unhappy in a small tank, which will lead to a weak immune system. They may even end up dying because of this.

In case you have a small aquarium, here is a list of fish that are better suited for small aquariums.

Can an Aquarium Be Too Big For a Betta?

Like we’ve established before, betta fish can be placed in a tank of any size, but the bigger the tank is, the happier your fish will be. Bigger aquariums offer more room for these territorial species to explore and swim around.

Besides the size of the aquarium, you need to focus on the environment of the tank if you want your betta fish to be happy.

Bettas prefer a habitat that is full of hiding places. If your large tank doesn’t have any plants or toys/decor items, your betta fish can be pretty stressed out and upset. So, even if you’re opting for a large aquarium, ensure that it’s equipped with a lot of hiding places and plants.

Even though a large tank is preferable for betta fish, avoid opting for an aquarium that is too deep.

Betta fish have a labyrinth organ. They have to go up to the surface of the tank to breathe. If your aquarium is too deep, they might face some issues in reaching the top of the tank. The probability of your Betta fish dying this way is super low, but they may experience stress.

As long as you decorate your tank well and provide perfect hiding spaces, your tank will never be too big for your fish.


The bottom line is that opting for a big tank is your best bet— preferably a 5-gallon tank (at least).

If you want to host many betta fish or other types of fish, you can opt for a bigger tank, preferably a 10-gallon tank.

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