how many betta fish in a 10 gallon tank

How Many Betta Fish in a 10-Gallon Tank? The Ultimate Guide

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Male betta fish are extremely aggressive towards each other and can only be kept together in the same tank if it has a carefully designed divider.

Female bettas are less aggressive and can sometimes be kept together in a sorority tank, but is a 10-gallon tank really big enough for that?

Here we’ll explore all the options for keeping multiple bettas in 10-gallon aquariums, as well as look at some other tank mates that aquarists could try in a nano tank.

Keeping Male Bettas Together With a Tank Divider

Male betta splendens are so aggressive they’ve even earned themselves the name ‘Siamese fighting fish’. In Asia, males are sometimes pitted against each other in cruel contests where they fight to the death.

So, keeping two males in the same tank is obviously never an option – without a divider that is.

Betta tank dividers are typically made from some kind of permeable glass, plastic, or mesh barrier that separates two or more males in a single tank.

A good enough concept, but how well do betta tank dividers work well in reality? Let’s look at the pros and cons.

Advantages of a Betta Tank Divider

The obvious advantage of a betta tank divider is that it allows you to keep multiple male bettas in a single tank. It’s also cheaper than buying two betta tanks.

But there are some hitches, too!

Problems With Betta Tank Dividers

A potential unseen issue in betta tanks with a divider is that your male bettas may still flare and spar with each other from each side of the divider, causing a lot of stress and even minor injuries.

Another common issue is uneven water circulation between the chambers. Whereas one side may have too much water flow from the filter, the other side can become stagnant – either of which can be very harmful to betta fish.

Finally, people will sometimes try to cram too many chambers into a small tank. Cramped compartments of less than 5 gallons are simply too small for betta fish to remain happy. In such a tight space, your bettas may die prematurely.

How To Make a Betta Tank Divider the Right Way

Just because there are some potential drawbacks to betta tank dividers, it doesn’t mean that we need to write them off altogether!

Here’s how you can make it work:

Keep Your Bettas Out of Sight From Each Other

First, we need to make sure that your betta fish can’t see each other between the divider so they don’t flare and fight over the barrier.

For this, you’ll need to make the divider from some type of fairly opaque material such as colored, water-safe PVC, or acrylic. A dense, dark-colored mesh may also be sufficient to keep the fish out of sight from each other.

Place a Sponge Filter on Both Sides

The problem with power filters in a divided betta tank is that the flow will be too strong on one side, and too weak on the other.

To solve this, try using two small, low-powered sponge filters on each side. Sponge filters are incredibly cheap, and you don’t even need to buy separate air pumps – simply use a reliable one with dual outlets like this!

Uniclife 64 GPH Aquarium Air Pump with Dual Outlets Adjustable Quiet Fish Tank Air Pump with Air...
  • Steady Output: Max Air Flow Rate: 64 GPH; Pressure: 0.016 MPa; Power: 4 W. Perfect for aeration in 10 - 100 gallon fresh water and marine aquariums.(The data is measured with experimental equipment and may deviate slightly from the actual data. The air volume may be insufficient due to the blocked air intake cotton. Please replace the cotton yourself if the air volume is insufficient.)
  • Adjustable Air Flow: Feature a rotary knob to control the amount of air for dual outputs, allowing for your desired air flow to fully oxygenate your fish tank.
  • Quiet Operation: The pump emits 25 dB sound under the “Low” mode and maximum 45 dB noise like the hum of a refrigerator under the highest air flow.

How Many Male Bettas Can You Keep in a 10-gallon Tank?

Since each male betta fish should have at least 5 gallons of free swimming space, you can only keep two males with a single divider in a 10-gallon tank.

If you want to keep 3 male betta fish with dividers, you’ll need at least a 15-gallon tank. For 4 bettas, you’ll need a 20-gallon tank.

Keeping a Female Betta Sorority in a 10-gallon Tank

Now, while male betta fish are extremely aggressive towards one another, females are rather more peaceful fish. This doesn’t make them altogether docile though – females are more than capable of picking fights with each other!

Opinions are divided over whether keeping groups of female bettas is worthwhile or even ethical. Because these fish can still fight with each other, bullying isn’t uncommon, and that can lead to unnecessary casualties.

The Minimum Number of Female Bettas in a Sorority

To provide the most peaceful possible setup, it’s recommended not to keep less than 4-5 females together. This is because more fish help to divide up and disperse aggression between tank mates.

If you were to keep an aggressive dominant female with just one or two others, the weaker fish would simply receive too much aggression and would likely become overwhelmed and stressed. Constant harassment could lead to injuries and even death.

Is a 10-gallon Tank Big Enough for a Female Betta Sorority?

Since a 10-gallon tank is only large enough for 2 or 3 female betta fish, I wouldn’t recommend it for a betta sorority.

As we’ve discussed, female bettas should never be kept in groups of less than 4 individuals, and a 10-gallon tank is simply too small for 4 betta fish.

Although other aquarium fish could be kept in such a high stocking density, doing so with female bettas is asking for trouble. In such a tight space, territorial disputes are bound to arise, resulting in needless stress, injuries, and potentially fatalities, too.

What’s the Minimum Size Tank for a Betta Sorority?

The minimum number of fish in a betta sorority is 4, but 5 or more is better. For 5 female bettas, I’d recommend a minimum of a 20-gallon tank.

While you could keep just 4 females in a 15-gallon tank, imagine if one of them dies. You’d be left with the unfeasible number of 3, and a replacement fish introduced later is more liable to get bullied.

To be on the safe side, then, go for more fish in a bigger tank.

How Big Does a Betta Breeding Need To Be?

If you’re thinking about breeding betta fish, you’d better know what you’re doing! A betta fish’s courtship ritual is a notoriously aggressive affair, and can easily result in the death of the female.

It’s for this reason that breeding betta fish is normally left to experts and professional breeders. But in case you’re wondering, a 10-gallon tank is a popular size for a betta spawning tank.

You can find out more about breeding betta fish by visiting our dedicated breeding pages here.

What Other Fish Species Can Live in a 10-Gallon Betta Tank?

Now that you know keeping betta fish together in a 10-gallon is full of potential complications, you may be wondering what other fish species and invertebrates you can keep with them!

Here are some of the best:

Corydoras Catfish

Cory catfish are some of the best tank mates to keep with betta fish. Not only are they incredibly robust and peaceful, but they also do an outstanding job at eating up leftover food, keeping the tank clean and the water quality high.

But because cories like to be kept in groups of 5 or more, I’d only recommend the smallest cories for a 10-gallon betta tank.

The Dwarf cory (C. hastatus), and the pygmy cory (C. pygmaeus) are tiny fish, only reaching about an inch long at maturity, meaning you could keep a small school of them alongside a single betta in 10 gallons of water.

Freshwater Shrimps

Another great family of tank mates to keep alongside bettas in a small tank are freshwater shrimp. Cherry shrimp, ghost shrimp, and Amano shrimp all make peaceful and suitable tank mates for betta fish, and like cories, do a sterling job of keeping the tank clean.

Growing up to 2 inches long, Amano shrimp are one of the largest of the most commonly kept aquarium shrimps and therefore stand a better chance of resisting any aggressive behavior from your betta.

They are also some of the best algae eaters, and unlike the others, don’t breed in freshwater, so will never overpopulate your aquarium.

Aquarium Snails

Freshwater snails make some of the best tank mates for betta fish, but note that most aquatic snails can breed in fresh water and can therefore quickly overrun a 10-gallon aquarium!

Nerite snails are beautiful black-and-white striped snails that don’t eat aquarium plants and don’t breed in fresh water. With a shell of up to an inch in diameter, they’re also large enough to fend off all but the most ferocious betta fish!

Just like the fore-mentioned tank mates, nerite snails are expert tank cleaners. Besides being one the best algae eaters, they’ll also clean up bits of uneaten food left behind by your bettas, thus preventing them from polluting the tank.

Schooling Fish Are Better in 20-gallon Tanks

While some people have tried to keep schooling fish such as ember tetras, rasboras, and danios in 10-gallon betta tanks, this aquarium size is rather too small for them to remain happy and display their true schooling behavior.

In such a small space, they’ll tend to scatter out and bob around in the tank instead of forming the beautiful tightly knit schools that they would in the wild.

This dispersed ‘hovering’ behavior also makes them more vulnerable to attack from your betta. Stressed fish such as neon tetra are also more likely to nip your betta’s fins.

Do yourself and your fish a favor by getting at least a 20-gallon for schooling fish. It will be more enjoyable for them to swim in, and more pleasurable for you to watch, too!

Warning: No Tank Mate Is Safe From an Aggressive Betta Fish!

Although some types of fish are better tank mates than others for betta fish, there is no guarantee that any species will be safe from a killer betta fish!

Some bettas are so aggressive, they’ll attack anything that moves, including any tank mates, their owner’s hands, and their own reflection! Even the biggest, toughest snails like mystery snails aren’t safe from an irate betta, meaning you may have no choice but to keep them in their own separate tank!


Male betta fish can only be kept together in a tank with a divider, but you need to make the divider perfectly for it to work well!

While female bettas can sometimes be kept together successfully, a 10-gallon fish tank is too small for this. I’d recommend a minimum of a 20-gallon tank with 5 females for a betta sorority setup.

Other fish and shrimp can sometimes be kept with betta fish in a 10-gallon tank, although an extremely aggressive male betta will always need to be kept alone!

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