Betta in a bowl

How Long Can a Betta Fish live in a One Gallon Tank? Find Out the Minimum Betta Fish Tank Size

6 min read

Betta Fish

Seems like everyone is keen on getting a betta – also known as the Siamese fighting fish – as a pet. Unfortunately, not everyone has the proper setting for them. One of the most important things to consider is the betta fish tank size. 

Aquarium enthusiasts are dead set on pushing the limit when it comes to tank size, not caring about the wellbeing of their fish. And the betta fish is the usual victim.

Can a betta fish live in a one gallon tank?

The answer is a little more complicated than you’d think, which we’ll discuss in this article. We’ll also look at how much water a betta fish needs.

Read on and find out whether a one gallon betta tank is really such a good idea.

Can a Betta Fish Live in a One Gallon Tank?

It may come as a surprise, but a betta can indeed live in a one gallon tank. That is, provided you maintain proper conditions for them – something easier said than done with a one gallon tank, as we’ll see later.

If you walk into any betta fish store, you’ll probably see them swimming in small tanks, bowls, or even cups. So it is not that strange to see a betta in a one gallon tank.

But here’s the catch: a one gallon tank is not ideal for a betta – it can reduce their lifespan by a few years.

Therefore, the real question you should be asking is, should your betta fish live in a one gallon tank? The answer is a big no.

So what about the pet stores?

Well, first, the bettas don’t stay that long in the store. Most of them will be sold within a short period, so hopefully they don’t live in bowls that long (except for the poor souls that don’t get sold!).

Second, I have a feeling that the wellbeing of the fish is not nearly as important as profit for most stores – it is much easier and cheaper to store and transport bettas in bowls than in large tanks.

The stores shouldn’t keep them in a one gallon tank and you shouldn’t either.

Problems with a one Gallon Betta Tank

The issue with a one gallon betta tank is the water quantity. With such a low amount of water, it becomes nightmarishly hard to maintain the ideal conditions for your betta, leading to a fragile ecosystem. It can cause the following problems.

Low Oxygen 

Your fish needs sufficient amounts of dissolved oxygen to breathe underwater. In a one-gallon tank, oxygen can deplete pretty quickly when something goes wrong.

For example, if your air pump stops working, or if you have a lot of decomposing waste, the oxygen can drop really low before you can react to it.

Luckily, bettas are labyrinth fish, meaning they can breathe air directly. They can’t do that if you have a closed-top tank, however.

Rapid Fluctuations in Temperature or pH

A one-gallon fish tank can quickly change in terms of temperature or pH. A bigger tank can resist those changes because of the amount of water.

As betta is a tropical fish, they require a temperature of 72-82° F. Temperatures lower than 60° F can put undue stress on them and lower their immune system. 

That means if your heater stops working in the middle of winter, your betta will be in trouble.

On the other hand, if the heater thermostat malfunctions, it can even cook your fish alive as the small amount of water heats up fast.

Build Up of Toxic Chemicals

Ammonia is one of the biggest fish killers in aquariums. It is excreted by your fish, while some are produced through the decomposition of organic waste.

Any concentrations above 2500 ppm can be fatal to your fish. The keyword here is concentration, which takes into account the volume of water.

So in a one gallon tank, the concentration of ammonia can rise pretty rapidly, killing your fish. 

The same goes for other toxic chemicals such as nitrite, chlorine, etc. Even nitrate can kill your fish in large enough amounts. 

A bigger tank can dilute any toxic chemicals, giving you more time to deal with it.

Depression and Stress in Your Fish

Yes, your fish can get unhappy too. You’d know this if you are a sharp observer of aquariums.

This is especially true for an intelligent fish such as a betta. A betta fish loves to explore and interact with its environment, but there can’t be much of an environment in a one-gallon tank. There’s simply not enough room, and there’s barely any hiding spots.

How would like it if you lived in a closet? The same goes for your betta.

Betta fish in a one gallon tank

How Long Can a Betta Fish Live in a one Gallon Tank?

If you are still adamant enough to keep your betta in a one gallon tank, you should know this:

A betta can live just 1-2 years in a one gallon tank. The average lifespan of a healthy betta is 2-5 years, while some are known to live for even 7-8 years.

So you are taking many years off your betta’s lifespan by subjecting them to a one-gallon tank.

Technically, it is possible to keep your fish healthy in such a small tank, but only if you diligently maintain the water conditions, which puts an undue burden on you, the aquarium keeper.

Even then, it will simply be a matter of time before disaster happens.

For instance, a one gallon tank may need a water change every other day – forgetting it just for a couple of days can result in your betta fish dying. 

Making matters worse, it will be difficult to add filters, heaters, and other vital components to your one gallon tank, as space will be limited.

So, all in all, one gallon is not enough for a betta fish.

How Much Water Does a Betta Fish Need?

So if a one gallon tank is not enough, how much water should a betta fish have?

Your betta fish needs at least 2.5 gallons of water. That is the minimum beta fish tank size. The ideal amount is 5 gallons.

Remember, the more water you have, the easier it is to maintain. So be liberal with the water to make things easier for you – your betta will appreciate it too.

The above recommendation is for a single betta fish; more than one obviously requires much more water.

It is next to impossible to have more than one male betta fish per tank, as they are highly territorial and will often fight to the death (they are called Siamese fighting fish for a reason).

You should have 20 gallons of water before you can even think of keeping more than one male betta fish.

You can introduce three to five female bettas to keep the male company, however. For that, you need at least 10 gallons of water.


As you have seen, a betta fish can live in a one gallon tank. However, things are not ideal with that tank size and their lifespan will be significantly reduced.

A one gallon tank will also tire you out as you feverishly try to maintain the optimal conditions for your betta – things are much easier with a larger tank.

A betta fish needs a minimum of 2.5 gallons of water; the more water you have, the better.

So for the sake of yourself and your fish, get something bigger than one gallon for your aquarium and watch as your betta swims happily in its big new tank.

Thanks for reading.


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Pet Aquariums

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