Betta Fish: Recommended Tank Size And Requirements

I recently decided to get a betta fish (or Siamese fighting fish) for my son. However, we are a bit short on space at home, so I was wondering just how big of a tank a betta fish requires. Having done some research here’s what I found.

So, what is the recommended tank size for a betta fish? The recommended tank size for a single betta fish is at least 5 US gallons (18.9 Litres). Although betta can survive in smaller tanks, it can be difficult to establish a stable nitrogen cycle and regulate temperature. The larger the tank, the less maintenance needed to keep your betta fish healthy.

When it comes to keeping betta fish, there are a few misconceptions regarding their habitat and requirements. When selecting a tank that is suitable for you and your betta fish, it’s useful to have an idea of their natural environment.

What Is The Natural Habitat For Betta Fish?

A common misconception is that bettas originate from small puddles of water and may become stressed if kept in large tanks.

In fact, the natural habitat for betta fish is in the marshlands, streams and rice paddies of Thailand and Cambodia.

While these can be relatively shallow, they are actually vast bodies of water with varied ecosystems, rich in vegetation. In most cases, they’re also deeper than the average fish tank.

The misconception that bettas come from small puddles may have something to do with the fact that bettas are labyrinth fish. Labyrinth fish have a specialized organ which allows them to extract oxygen at the water’s surface.

This allows bettas to tolerate living in small unoxygenated puddles for short periods, which is helpful should they become trapped in the dry season.

However, this situation is less than ideal for them and bettas also have excellent jumping abilities, which aid their escape into larger bodies of water.

This is why a tank no smaller than 5 US gallons is recommended. Although bettas can survive in smaller volumes of water, they will certainly not thrive.

Besides giving them more space to roam around and spread their fins, in a larger tank, it takes much longer for ammonia and nitrates to build up to a dangerous level.

If you have space (and money) for a bigger tank, your fish will be far better off and there will be less work required on your part to keep it free of toxins.

It is also very difficult to regulate temperature in anything smaller than 5 gallons. Fluctuations in temperature can be dangerous for your fish.

When picking your tank, I would also recommend getting a lid or some sort of cover on your tank. This will reduce water evaporation, which can lead to an excessive mineral build up in the water over time.

A lid will also prevent your fish from jumping out of the tank if conditions become less than ideal.

What Do Bettas Like Inside Their Tank?

After selecting your betta tank, there are a few other requirements which you will need to consider in order to create the best environment for your betta fish.

Considerations for a betta tank setup:

  • Water Filter
  • Tank Heater
  • Substrate
  • Ornaments & Plants
  • Lighting

For each of these points, there’s lots of information and considerations to make. I will give a brief overview of each point in the rest of this article, so you should have a good idea of how to set up your betta tank.

Do Betta Fish Require A Filter?

Many people think that bettas do not require a filter seeing as they come from slow water habitats. However, I would highly recommend that you do get one.

The main purposes of filters in fish tanks are:

  • To remove floating debris for clearer water
  • To prevent the build-up of toxins such as ammonia and nitrates
  • To Aerate and oxygenate the water

It’s true that betta fish are comparatively clean and do not foul their water as quickly as many other species such as goldfish. That said, every time you put food in the tank or your fish goes to the toilet, the water becomes a little dirtier and toxins begin to accumulate.

If you do not have a filter in your tank,  you may have to change up to 50% of the water in your tank every few days in order to prevent the water from becoming toxic (depending on the size of your tank and the quantity of fish).

This can be very time consuming not to mention, a stressful process for your fish to go through every few days.

Having a filter in the tank will significantly reduce the requirement for frequent water changes. In effect, the better the filtration system, the less hard work for you to maintain water quality and the healthier your fish will be.

Although betta fish do have the ability to take in oxygen from the surface, having well-oxygenated water will still be beneficial for your betta.

One thing to bear in mind when selecting a filter for your betta fish is that their large flowing fins make it very hard for them to swim in stronger currents. For this reason, you should be sure to select a gentle filter or one that you can adjust the flow settings on to create the optimal current.

Do I Need A Heater For My Betta Tank?

As bettas come from south Asia they are definitely suited to warmer temperatures.

If the water temperature is too cold, they tend not to move around much and will often float near the bottom of the tank or on one side. The cold temperatures slow their metabolism and put a strain on their immune system, making them far more susceptible to illness and diseases.

If the water temperature is too warm on the other hand, fish will often exhibit erratic and rapid swimming patterns. It also speeds up their metabolism, which in turn actually causes them to age faster, shortening their lifespan.

Betta fish can survive in temperatures ranging from 72-86° F (22.2-30º C). However, in order to thrive, their ideal temperature range is 78-80° F (25.6-26.7º C).

Unless their tank is situated in a very warm room which allows the water temperature to sit consistently at 78-80° F, you will need a thermostatic tank heater.

You will also need a separate thermometer in order to monitor the water temperature inside your tank. Even if your heater has it’s own built-in thermometer, it’s best to have an independent one, as the built-in thermometers tend to be quite inaccurate.

The Best Substrate For A Betta Fish

When it comes to adding substrate to your betta tank there are lots of options available. However, there are a couple that stand out for me. Those being sand or gravel.

One of the main reasons for adding substrate to your tank (aside from the aesthetics) is to act as a medium for harboring beneficial bacteria responsible for the breakdown of organic waste.

These bacteria can grow on any surface in the aquarium. Adding substrate adds surface area for the bacteria to colonize. The more good bacteria, the more stable the nitrogen cycle and the healthier your tank will be.

Another reason for adding substrate is for plants to anchor themselves and to and absorb nutrients from. There are soil type substrates which will provide nutrients for plant life, however, these are a little specialized and are mainly used by planted aquarium hobbyists.

I wouldn’t recommend these for a beginner’s fish tank. Soil substrates are a little messy and can put a strain on your filtration system.

Sand and gravel both have a great deal of surface area. They are readily available and are fairly easy to maintain, making them great options.

While they do not add any nutritional value, a lot of plants suitable for bettas will only really require something to anchor themselves into so they can take their nutrients from the water.

There are pros and cons to both sand and gravel.

Pros And Cons For Using Gravel Substrate In A Betta Tank

Pros for using gravel:

  • Available in various shapes, sizes, and colors to suit preference.
  • Hides organic waste for a tidy looking tank.
  • You can be fairly aggressive to clean down deep when gravel vacuuming.

Cons for using gravel:

  • Can often fade or become discolored over time.
  • Hard to tell if all organic waste has been removed when cleaning.
  • shifts around more than sand. Plants may become unanchored more easily.

Gravel is my first choice for a betta tank. I would recommend it to anyone, particularly beginners.

Generally speaking, larger gravel is more suitable for larger fish so I would go for a fairly small size for a betta. Uneaten food and waste do not get so easily trapped, making it slightly easier to clean.

Also, If you select smooth grained gravel, as opposed to jagged edges, there is less chance of your betta damaging its fins, particularly for males.

Pros And Cons For Using Sand Substrate In A Betta Tank

Pros for using sand:

  • More akin with the bettas substrate in the wild.
  • Has a more natural and professional look.
  • Toxic waste rests on the surface making it easy to tell if it has been removed.

Cons for using sand:

  • Needs raking or “fluffing up” from time to time to prevent gas pockets and the build-up of dangerous toxins.
  • As organic waste is very visible, it can look very untidy soon after cleaning.
  • More care is required when gravel vacuuming so’s not to lose substrate. It’s also harder to clean when initially adding it to the tank.

Sand is my second choice. It can be a little more work so I would only recommend using it if you prefer the aesthetics and the extra work doesn’t phase you.

Pool filter sand is one of the better options if u do not want to fork out a lot for aquarium sand. Just ensure it’s silica as opposed to zeolite which will harm your fish.

Some people use play sand, however, it is a lot finer than the pool filter sand. It clumps together more and can make the water cloudy particularly when disturbed.

When gravel vacuuming, it’s best to hover slightly above the surface if you don’t want half of your substrate to disappear.

Plants And Ornaments For Betta Fish

In the betta fish’s natural habitat there is plenty of dense vegetation and shady hiding spots. They can be quite timid fish so they will need places where they can hide and feel safe or they may become stressed and unwell.

Live plants present a natural surrounding for your fish, as well as helping to oxygenate and improve water quality. They will be a welcome addition to your betta’s tank and as they are great for providing the cover that your betta fish needs.

Fake plants are also an option and will provide equally good cover for your fish. Personally, I don’t like the way fake plants look but on the positive side, you won’t have to worry about maintenance or plant matter floating around in your tank.

Should you choose to use fake plants, it’s advised to use silk as opposed to plastic ones. Plastic plants often have hard edges which can damage a betta’s delicate fins.

Although silk plants are slightly more expensive, they are safer for your fish and they tend to look more natural too.

When selecting ornaments for your betta, you should also keep their delicate fins in mind. Ensure the ornaments do not have any features that may snag or tear your bettas fins.

Betta Tank Lighting

Betta fish, like most shallow water fish, are exposed to sunlight in the wild. They benefit from having a daytime/nighttime cycle which helps with their circadian rhythm and sleeping patterns.

They generally need around 8-10 hours of light and 12-16 hours of darkness each day.

As with many other aspects of keeping fish, It’s best to replicate their natural habitat as best as possible. In a room with plenty of natural sunlight, lighting isn’t absolutely a necessity.

However, direct sunlight can lead to algae bloom and raised temperatures, particularly in smaller tanks. Both of which can be hazardous to your fish’s health.

Artificial light offers more control over your bettas daytime/nighttime schedule and reduces the chances of your tank overheating. It looks great too!

Artificial light can also be beneficial for plant life in your tank. Different types of plants will require different levels of lighting so be sure to do your research for your particular plants.

If your tank does not already come fitted with lighting there are plenty of cheap options out there.

  • LED Lighting – The best option. Very economical. Doesn’t produce any heat.
  • Fluorescent lighting – Still a good option. Fairly economical. Produces a small amount of heat.
  • Incandescent lighting – Avoid this option. Uneconomical. Produces a lot of heat. Can break when splashed if switched on.

If your willing to spend a little extra, I would recommend purchasing a timer switch. This will really help with your bettas daily cycle.

If your bettas tank is kept lit for too long then it can lead to overstimulation and stress. Stress weakens the immune system making your fish susceptible to disease and ill health.

On the other hand, if the tank is too dark, your betta may be understimulated and over time darkness can lead to loss of color in your betta.

However, there are many possible reasons for color loss in bettas. If this happens to your fish be sure to rule out any other possibilities.

Related Questions

Can you keep multiple Betta fish together? Multiple female betta fish can be kept together in the same tank, however, males should always be kept separately as they are territorial and will fight with each other. Males shouldn’t be kept with females except for short periods for the purpose of breeding, as they can also become aggressive.

Can male bettas live with other fish? Male bettas can live with certain tank mates so long as the tank is big enough. They mix best with smaller more passive creatures such as corys, loaches, small plecos, snails, shrimp, ADFs, and groups of tetra or harlequin rasbora. However, some bettas may never integrate into a community tank.

How big do betta fish grow? In ideal conditions, an average betta fish can grow to 2.25 inches (5.7 cm) in length. In some instances, they can reach up to 3 inches (7.6 cm) long. However, some breeders claim to have bettas measuring over 5 inches (12.7 cm) in length as a result of extensive selective breeding.


Mark Ingram

Thanks for taking the time to read this article. I hope that it was informative and useful in some way. I love all of my pets and their care is paramount to me. I hope that my writing will help others in caring for their pets also.

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