What is the Minimum Tank Size for a Betta Fish

What is the Minimum Tank Size for a Betta Fish?

Minimum Tank Size for a Betta Fish

When people first get their betta fish, they often keep them in inappropriately sized tanks. Many pet store employees are trained to give an overview of the care of several hundred species of pets, so there is some misinformation passed around, and unfortunately, this often includes common misconceptions about betta fish. In particular, there are common misconceptions that bettas cannot be kept in large tanks and do best in very small tanks. Is this true, and if so, how small of a tank can you keep a betta fish in?

The minimum tank size for the average betta fish is 5 gallons, though some bettas with excessively long fins (to the point that they have impaired swimming) can live in 2.5- to 3-gallon tanks. Betta fish are still active creatures and need room to swim, though this is not the only reason for their minimum tank size. The primary reason is that toxins build up incredibly quickly in small tanks, and small tanks are much more difficult to care for than large tanks.

In this article, we will discuss whether 1-gallon tanks are appropriate for bettas, whether large or small aquariums are easier to care for, if it it cruel to keep bettas in small tanks, why bettas traditionally live in small aquariums, and what happens if you put a betta in a large tank or pond.

Is a 1-gallon Tank Okay for a Betta?

A 1-gallon tank is not acceptable for bettas, as it does not provide enough water to dilute toxins, regulate temperature, provide room for a filter and heater, nor does it give your betta enough room to be active. Tanks ranging from a quarter of a gallon to a gallon are commonly sold and stated to be for bettas, but in reality, they are not large enough to house any fish, not even the smallest fish sold in the aquarium trade (which rarely reaches over half an inch in length).

Toxins, which we will discuss in more detail in the next section, come from fish waste and uneaten food. These toxins need to be biologically neutralized, which your filter is essential for. However, if too much toxins build up, they will poison the bacteria that make the water safe for your fish. This creates an even larger spike in the toxins, which often results in fish death.

When you are dealing with a fish in a very small volume of water, there is not enough water to dilute the toxins to a safe level, unless you are doing one or more daily water changes. Betta fish live an average of 4 years, with 7 years not being uncommon. However, due to a large majority of betta fish owners keeping them in ridiculously small aquariums, most people believe their lifespans are only a few months long.

Why are Large Tanks Easier to Care for than Small Tanks?

While it may seem counterintuitive for someone just starting out in aquariums, larger tanks are much easier to care for than smaller tanks. Small tanks often experience severe temperature swings, pH swings, and variable levels of ammonia, nitrite, and nitrate. However, larger tanks are not subject to such things due to the large volume of water.

It is easier to keep the water parameters stable in a larger tank, and stability is key when keeping fish. Frequent changes in water parameters cause severe stress to fish, sometimes enough to kill them. If the parameter changes of a small tank aren’t enough to kill your fish, the toxin buildup will be.

Unlike any other pet, fish live in closed systems. Anything that is in the aquarium will stay there until you remove it, which includes fish waste. Fish waste dissolves directly into the water column, which is quite harmful. Once dissolved, the waste produces ammonia, which bacteria convert to nitrite after 1-2 weeks. Next, a different type of bacteria convert it to nitrate after another 1-2 weeks. Once fully cycled, the bacterial colonies will be large enough to turn ammonia into nitrate after a few hours.

Ammonia is highly toxic and leaves severe chemical burns on your fish. While the burns themselves are bad enough, they often leave permanent, or even fatal, damage to the gills. Nitrite is even worse, binding to hemoglobin in the blood and preventing it from carrying oxygen, which suffocates your fish.

In a small tank, the waste from a single betta is enough to cause death within a few days. The waste from one betta in a larger tank will not be able to build up to a harmful level. A water volume of 20 gallons or more will easily be able to dilute the waste from a single betta.

Is it Cruel to Keep Bettas in Small Tanks?

Betta fish are very intelligent animals, capable of recognizing their owners, reacting to different people individually, having a memory span of over a year, and can easily be taught to do tricks. They are interactive and enjoy playing with their environment both inside their aquarium and outside.

However, if you keep your betta in a small tank that doesn’t have room for fun decorations or room for adequate movement, your betta can actually become depressed. Identifying mental illnesses in animals is rare, but scientists have been able to identify depression in bettas kept in poor conditions and have even been able to successfully treat them with antidepressants.

Aside from the damage that ammonia, nitrite, and fluctuating parameters cause, keeping a betta in a small aquarium is cruel, as it does not provide enough room to be active. While the average view of a betta is a lazy fish that hardly swims around, this only applies to depressed and/or sick bettas, and normally ones kept in small tanks.

If you move said betta into a larger tank, they normally perk up after a few days and become more active. If you place a single betta fish into a 20-gallon tank, or even a 55-gallon tank, they will swim around and use every single inch of the space provided to them. They truly are active animals, and keeping them in small cramped containers is cruel, as they have the capacity to feel unhappy with their surroundings, and the capacity to feel pain from chemical burns and suffocation.

Why are Bettas Kept in Small Tanks and Cups?

Bettas are normally shipped in small cups, while other fish are usually bagged and placed into larger tanks at the pet store. The primary reason that bettas are kept in cups is because it is very difficult to keep bettas with other fish, unless you can provide them with adequate space, which most pet stores simply can’t do. Bettas are shipped individually and have to be kept individually, so keeping them in small containers is the most efficient way to do so, from an economic standpoint.

Other fish, such as tetras, goldfish, and rasboras, can be bagged together and shipped, sometimes several hundred fish to a bag. If this was common practice for bettas, it would be a bloodbath.

Bettas “live” in small containers simply due to the ignorance of new owners. They see bettas in small cups and see a slightly larger tank for sale near the bettas. They then assume that it is acceptable to keep them in such a horrendously small tank. Some pet store employees even tell people that bettas prefer small tanks and will drown in large tanks.

What Happens if You Put a Betta in a Large Tank or Pond?

The myth that bettas will drown in large tanks is very common, though the source of the misinformation is unknown. Betta fish are, well, fish, and have very functional gills. They are adept swimmers, thrive in large tanks, and are less likely to drown than other fish.

Bettas naturally come from slow moving, warm rivers. Slow water has little gas exchange, meaning there is not much dissolved oxygen, and warm water cannot hold as much dissolved oxygen as cooler water. This means that the natural habitat of a betta has very little oxygen, and many fish are not capable of living in such conditions.

However, bettas have a secret weapon to overcome the natural lack of oxygen; the labyrinth organ. Bettas have a specialized organ similar to a primitive lung that allows them to extract oxygen from the atmosphere. Not only do they have perfectly functioning gills, but they also have primitive lungs. This means that if the oxygen in the water is running low, they can also get oxygen from the air. Most other fish are incapable of doing this, meaning bettas are more likely to survive in low-oxygen environments.

If you put a betta in a large tank or a pond, they will be extremely happy, and use the entire space. They do not have any increased risk of drowning and will likely live a much longer lifespan if kept in a large tank.

In conclusion, the minimum tank size for the average betta fish is 5 gallons, as this provides enough water volume for some toxin dilution, stable water parameters, and swimming space. Larger tanks are normally much easier to care for, especially for beginners, and there is no increased risk in keeping a betta in a larger tank, so go as big as you want!