How many betta fish can be in a 1-gallon tank?

In this post, we will answer the question “How many betta fish can be in a 1-gallon tank?”. We will also discuss why small tanks are not appropriate for betta fish.

How many betta fish can be in a 1-gallon tank?

No, betta fish cannot live healthily in a 1-gallon tank. These fish require some room to swim and develop properly. Thus, it is also important to consider some space for tank features, such as equipment and decoration.

Small betta fish tanks

If you’re contemplating buying a betta fish, I hope you’ve given some consideration to what sort of tank might be appropriate for him. In numerous of my articles, I cover the optimal tank size and setup for bettas, and my unequivocal and steadfast recommendation is to keep a single fish in a tank with a capacity of at least five gallons in size. If you intend to keep your betta with other fish, you will need a significantly larger tank. 

Betta fish are tropical fish that require a lot of space to swim and ideal water conditions to survive. They must have access to clean, filtered water that is kept at a regular temperature of 75–80 degrees Fahrenheit. They require a hiding place so that they may feel comfortable when the situation calls for it, as well as a slow current that does not force them about the aquarium. 

The majority of the blame should be placed on the industry. Betta fish are mass-produced and promoted as disposable pets that may be kept in a plant vase or a little cube on your desk at your place of employment. According to my standards, this is both cruel and immoral, but sometimes people don’t hear or grasp the message until it’s much too late to intervene.

Why do betta fish need larger tanks?

Bettas are a kind of tropical fish

What you should know about betta fish is that they belong to the same family as tropical fish such as neon tetras, platies, and Angelfish. This means that they require optimal living circumstances to grow, and anything less will result in their extinction gradually (or possibly more quickly). 

They do, however, have adaptations that let them survive in settings where the majority of other fish would perish, such as deep water. The fact that they are anabantids means that they can take in oxygen from above the water’s surface as well as breathe through their gills like other fish. If they live in pools of stagnant water, they have the potential to survive in the wild during times of aridity. 

This is why some people mistakenly believe that bettas should be housed in very small tanks, plant vases, cubes, and other ludicrous living arrangements where they would never attempt to keep another type of aquarium fish. One of the numerous betta fish misconceptions is that they love these sorts of conditions. This is not true. Just because your betta can live in such circumstances does not imply that they are optimal.

Tropical fish require proper filtration

Clean, wholesome water is essential for tropical fish, and a good filtration system is essential for keeping them healthy. Very tiny tanks are frequently equipped with air pumps that serve as filters, to establish some sort of under-gravel system. This is just not sufficient for maintaining the cleanliness of the water, especially in such a small tank. 

There are nano filters available for tiny tanks, however, one-gallon tanks have insufficient space for such a filter to function properly. Even yet, low-flow filtration systems are preferable for betta fish, and an aftermarket filter that propels them about the tank is detrimental to their stress levels. 

Due to the lack of a good filter, tiny tank owners must choose between performing weekly full water changes and cleanings or performing partial water changes in which only a limited amount of debris remains in the tank. Neither of these options is the best option. Keep in mind that keeping extra food and trash in the tank can soon contaminate the water, even after doing a partial water change. 

Microbial colonies in your tank can’t develop themselves after a complete water change. Microbes play an important role in the digestion of trash in your tank, and they also contribute significantly to the cleanliness of the water. If they are not there, the level of waste chemicals in the tank rapidly increases. 

You will find that choosing a tank that is capable of supporting an adequate filtration system makes these issues far more bearable.

Betta fish need warm water

Bettas demand water temperatures in the 75-80 degree range because they are tropical fish. This means that, in the majority of situations, you will want a dependable heater for the tank. Small tanks are typically equipped with heaters, which means that the temperature of the tank is governed by the temperature of the surrounding air. The weather may be good if you reside in an area where the temperature is consistently at least 75 degrees. 

For the majority of individuals, this implies that you are stressing out your betta by exposing him to freezing water temperatures. Even while a dip in temperature to 65 degrees at night may not seem like much to you, it may be quite stressful for a fish that is accustomed to warmer water. Even if it is warm during the day, the temperature in a one-gallon container will drop virtually as rapidly as the temperature in the surrounding air at night. 

There are various tiny heaters, such as micro heaters, that are intended specifically for bowls. My recommendation is to use them with caution in any tank that is less than five gallons in capacity. You must keep a constant eye on the temperature of your water to ensure that it is not being raised excessively. Just as cold water may be stressful or even fatal for bettas, water that is far too warm can be as harmful. 

Tropical aquariums are often bigger, which makes it simpler to maintain consistent water temperatures inside them. When you have a one-gallon tank, the odds are stacked against you, and your betta will suffer as a result of this.

Tropical fish require room to swim

You would not keep a dog in a closet, would you? He’d probably be alright if you fed him and took him for a walk a couple of times a day, wouldn’t you say? Perhaps you might install a glass door in the closet so that you can see him when he enters. 

Of course, you wouldn’t do something like that. Everyone, except the most unstable among us, would agree that such a thing would be cruel and immoral. Despite this, many of the same generally bright individuals believe it is OK to keep a fish in a tank where it has just enough room to turn around. 

Given that a dog is far more mentally complicated than a fish, the comparison does break apart a little bit in this case. The impact on fish housed in poor conditions in small tanks, on the other hand, is significant.

Small tanks are harder to keep clean and stable

A large number of individuals believe that a very tiny fish tank is the ideal option for an easy-to-maintain fish tank. The situation is just the reverse. Small ecosystems may develop in big tanks with the assistance of a well-designed filtration system and perhaps a few live plants, requiring the tank owner to provide just minimum effort. A 55-gallon tank may take as little as 30 minutes of weekly maintenance to keep it in good condition. All you have to do then is sit back and enjoy your catch!

Small tanks, on the other hand, must be closely monitored to ensure that they are operating properly. It doesn’t take long for things to go wrong to become disastrous. To maintain a one-gallon tank, you must be prepared to work on it once a week and be on the lookout for symptoms that the tank is becoming contaminated. 

When I say unclean, I don’t simply mean a build-up of physical waste, though it is something to keep an eye out for as well. Excess algal growth may be caused by a variety of factors, including overfeeding and improper tank placement. This harms water quality. An extra pinch of unwanted fish food can have a cascading impact on your betta fish that, if left unchecked, can result in very negative things happening to your betta fish. 

It is for this reason that diseases such as fin rot are so common in fish housed in tiny tanks. Because of the stress of living in a small space and the low water quality, the fish never gets a chance to reproduce. Because a 5-gallon tank is (obviously) five times larger than a one-gallon tank, a pinch of extra fish food will have less of an adverse effect on the fish.


In this post, we answered the question “How many betta fish can be in a 1-gallon tank?”. We also discussed why small tanks are not appropriate for betta fish.

If you have any thoughts or doubts, feel free to drop us a comment below!

Frequently Asked Questions (FAQs): How many betta fish can be in a 1-gallon tank?

Is a one-gallon tank preferable to the little cups that pet retailers use to house bettas?

Yes, a one-gallon tank is unquestionably preferable to the little cups in which bettas are kept at the fish store for the time being. A one-gallon tank is also preferable to a mud puddle, a glass of lemonade, or the inside of a washing machine for a betta. Simply because something is better does not imply that it is great or correct. 

What is the purpose of keeping bettas in cups in pet stores? 

Nothing is more heartbreaking than witnessing a dead betta in a couple of inches of water at the pet store counter. The notion that these fish can survive in these horrendous conditions with extremely high levels of ammonia, nitrites, and nitrogen dioxide is still prevalent in most retailers, which is based on the fact that they are labyrinth fish that can breathe atmospheric air when necessary continues to circulate. 

Is it cruel to raise betta fish in such little aquariums as these?

The simple fact is that confining the betta fish to a tiny aquarium is harsh and unjust to the animal. Many new fish keepers mistakenly assume that simply because these fish are offered in little cups at the pet store, they don’t require the same amount of room as other types of aquarium fish. Unfortunately, many individuals are ignorant and do not invest the necessary time to learn everything there is to know about caring for a betta fish, including how beautiful they can be when kept in the proper conditions.

What is the bare minimum suggested tank size for a betta fish aquarium? 

That being stated, it is critical to understand what size tank bettas require to be happy and healthy during their whole existence. Overall, a tank of 5 gallons or less is the bare minimum advised for maintaining one betta and potentially a snail or two as a houseplant. 

For how long do betta fish survive in a one-gallon aquarium? 

A Betta in a 1-gallon tank could be expected to live for less than a year at the most. 

What are betta stress stripes, and how do they work? 

Betta stress stripes are the result of your betta’s reaction to unexpected changes or adverse aquarium circumstances. Your fish’s vibrant colours may begin to fade, and light and/or dark vertical stripes may appear on the sides of its body as a result of this.


Eric Dockett. 2022. Why One-Gallon Tanks Are Bad for Betta Fish.

The Bets 1 Gallon Betta Tank… Not Suitable For Bettas.

Young, T., & Bone, J. (2021). A better life for betta fish. Every Child, 27(2), 8-10.

Song, M. (2006). Caring for Betta Fish. Lulu. with.