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What Is The Best Betta Fish Tank Size?

Betta fish are a real feature for any aquarium. They can really enliven a tank, and that is why they have become one of the most popular types of aquarium fish anywhere in the world.

Of course, Betta fish are well known for their territorial and potentially aggressive temperaments and personalities. This may be one of the major reasons for their popularity.

However, before you decide to purchase and care for one of these breeds, it is important that you do your research and understand the requirements that this fish has. Of course, this covers all sorts of criteria, including their diet, water chemistry and suitable co-inhabitants of the tank.

But one of the most crucial factors that any responsible tank owner needs to know is the space required for their fish. That’s why, in this deep and comprehensive article, we will explore exactly how much space the average betta fish needs, so you can gauge the correct betta fish tank size.

Choosing an improperly sized tank can have very dire consequences for your fish in the long term, so it is worthwhile to spend some time researching the topic now, before you commit to buying a tank.

What Is A Betta?

Video: “Amazing Betta Fish Facts”

A betta may be better known by its common name of the Siamese fighting fish. This popular name really gives the clue to its personality and general behavior. The betta is renowned for its displays of territorial aggression and will always try and exert its dominance in any enclosure.

In fact, this violent and aggressive streak has led to them being used in gambling spectacles in the past, though this blood sport has thankfully died out.

The betta is native to the shallow fresh waters of South East Asia. It is found in large quantities in the wild in countries such as Laos, Cambodia and Vietnam. It is also a very common sight in Thailand and is actually one of the national symbols of that country.

In the wild it is used to some very crowded and congested conditions, dwelling in the shallow paddy fields and flood plains of the region. The aggression that is so famous for is present in wild species, but it is more suppressed and nuanced. Thus, while betta fish may sometimes feud in the wild, this is only really common in mating season.

Domestic Species Of Betta Fish

In other conditions they like to avoid conflict. However, aggression has been selectively bred into the domestic species of fighting fish that are now sold for aquariums. Many generations of careful breeding has resulted in the extremely sensitive, irascible breed that is commonly sold to the public.

However, their nasty streak and aggression is not the only trait that has been purposefully bred for over the years. Bettas can also be a highly attractive and aesthetically pleasing fish. Although in the wild they are usually dull, earth colored fish, in captivity they can display much more vivid adaptations.

When they are not distressed, a betta can appear in vivid shades of orange or red, and brighter colors such as blue and green are even possible. Their arrangement of fins and their lively movements is another reason why they make such an attractive pet. If you can create a suitable ecosystem and living conditions for the betta, then it can certainly bring a lot of joy to its owner.

What Is The Ideal Betta Fish Tank Size?

For a long time, it was considered common knowledge that there was no minimum tank size for a betta, and that this hardy could survive for a prolonged period in bodies of water of any size. This idea originates in the conditions that they live in in the wild. See, during the dry season in their homeland, their watery homes can severely shrink in size.

They normally inhabit the flooded fields and riverbeds of Asia, but when they dry up, they can be left in tiny puddles of standing water. Since this is what happens to them in nature, people naturally surmised that they could survive in tiny enclosures in captivity.

In fact, we now know that this is not true. Like all other aquatic species, there is a minimum recommended size for a betta fish tank size. The minimum size for such a tank is 2.5 gallons. Placing your fish in a container any smaller than this will be very unhealthy for them in the long term and will inevitably lead to health problems.

Although this is the absolute minimum size for a betta fish tank, it is advised that your fish tank is actually greater than 2.5 gallons. A 2.5-gallon tank is only permissible for people who have a sever lack of space.

The 5 gallons should give your fish enough space to swim around, thus helping it to exercise its muscles and stay hale and hearty. It is also large enough for a stable equilibrium to be formed in the water.

Why Can’t I Put My Betta In A Smaller Tank?

Unfortunately placing your betta in a very small tank can have very serious and bleak consequences. Firstly, in a very small tank, your fish will not have enough space to roam about and fully exercise its muscles.

This limited mobility can not only quickly age your fish, but it can also lead to your fish become disturbed and distressed. It is well known that a distressed fish will not display its vivid colors, which is unfortunate for the proud fish owner as well.

Also, a fish tank is a fish’s toilet as well as its home. What this means is that fish naturally produce waste products as it digests its food. These waste products include substances such as ammonia and nitrates that can be toxic to the fish if they are present in sufficient quantities.

In a large and well-kept ecosystem, these substances are kept in check by ‘good’ bacteria which live in the tank, feasting on the waste products and breaking them down into harmless substances.

However, in a very small tank, it might be hard for these bacterial colonies to become established. This means it can be hard to establish a stable balance in the tank, and toxic substances can quickly threaten the health of the miniature ecosystem.

Can You Ever Have Too Much Space?

Since the betta as a species seems to be well adapted to living in confined quarters, many people wonder if there is a maximum size on the best betta tank? Is there such thing as having too much space?

Well, truthfully the answer is no.

Your betta will love having lots of space to roam and explore. This is especially true if your tank is well designed and filled with nooks and crannies. This can come in the form of rocks, aquatic plants, driftwood or ornaments.

Not only will all these features bring joy to your betta as they roam, but they will also add to the aesthetic appeal of your tank. Hence, it is recommended that you install the largest tank that is suitable for your budget and available space. However, if you do intend to keep a larger tank, there are a few things that you should keep in mind.

Cons Of A Large Betta Tank

First of all, it might seem obvious, but a larger tank means increased maintenance duties. If you have a large 20 or 50-gallon tank, then cleaning and changing the water can be a real issue. Of course, they are also able to take a bit more punishment and are not at such a danger to being quickly overcome by an algae bloom.

Nevertheless, you must really consider the amount of time you are willing to spend scrubbing the rocks, cleaning the glass, and doing partial water changes.

A larger tank also calls for a lot more resources than a smaller one. This manifests itself in many ways. For example, you will need to install a large and potentially expensive filtration system if you plan on having a large tank.

Major tanks call for a healthy capacity in terms of biological filtration and mechanical filtration. Biological filtration is necessary to keep control of the chemical substances in your water and make sure the waste is being properly broken down by bacteria.

Mechanical filtration is important for capturing dirt, debris and insoluble precipitates from the water. For a large tank you may have to install an expensive, canister type filter.

Also, the betta is a tropical fish, and therefore it tends to prefer warmer waters. If you live in a cold location, then this may necessitate you installing a heater in your tank.

If you own a very large tank then this can be an expensive initiative, as it drains electricity and adds to your monthly running costs. You may also be spending more on chemical treatments if you need to dose the water. All these additional costs can add up in the long run.

Can A Betta Fish Live With Other Fish?

If you are installing your betta into a very small tank, then it is likely that you will not have any room for any other tank mates. In any case, because of the highly capricious and territorial behavior of the average betta fish, you need to be very careful when selecting tank mates for this fish.

For example, you should never place two male fighting fish in the same tank. They are almost certain to fight, which will lead to injury or death of at least one of the inhabitants. You also need to be very careful when introducing female bettas. Sometimes males can mistake them for other males, leading to vicious attacks and deadly results.

If you do want to install a female companion for your male betta, make sure there is plenty of space (at least 10 gallons) and plenty of convenient hiding places for the female to shelter.

The same advice goes if you want to install other species. Make sure and increase the size of your tank accordingly and install lots of protective cover and little nooks and crannies. This will give them a degree of protection if your betta decides to lash out.

Other Tips

Video: “Decorate My Betta Fish Tank”

Other than getting the right betta fish tank size, there are a few things you should do to make the tank feel as spacious as possible. The first recommendation is to be clever with your decorating. Adding some driftwood or ornaments can certainly make your tank more attractive and visually interesting.

However, if you have a very small tank then you should not install large ornamental feature such as fake coral. These will just take up a lot of space and obstruct your betta fish from swimming freely.

Also, as well as the size of your tank, the shape is also important. Because of their origins in the wild, betta fish are naturally adapted to swimming horizontally, not up and down. Thus, you should ideally install a tank which is wider than it is deep. Otherwise you might put too much strain on your betta, leading to long term health problems.


In this article we have explored the issue of the correct betta fish tank size. We have shown that the strict minimum for any such fish tank is 2.5 gallons, but to be a really good owner your tank should be at least 5 gallons in size.

The problems associated with tiny tanks are well known and documented. They can lead to stunted growth, distressed fish and unhealthy ecosystems. On the other hand, very large tanks give your fish plenty of space to freely explore but can be time consuming and expensive to run.

Therefore, there is a delicate balance to find with regards to the correct betta fish tank size. Make sure not to over fill your tank with decor and plants, thus restricting the space available to your betta. Also, make sure that you choose a good wide tank, which suits the natural swimming style of betta fish in the wild.

Aaron Boyd
Aaron Boyd

Hello, I’m Aaron Boyd, the proud owner and author behind Aqua Movement. I hope my article was able to answer your questions. If you want to learn more about me, click the home icon above.

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