Can Guppies Live In a 3-Gallon Tank?

You can temporarily keep guppies in a three-gallon tank if you don’t have more than three males or two females. Guppies need a lot of freedom to remain healthy, and a three-gallon tank shouldn’t be their forever home.

When you get guppies for the first time, you may think they can live in any water container. Your eyes may fall on that three-gallon tank, and you could ask yourself: Can guppies live in a three-gallon tank?

There’s a difference between living and living comfortably. Stay with us for more clarification.

Can Guppies Live Comfortably In a 3-Gallon Tank?

It’s not directly harmful to guppies to live in a three-gallon tank. But it’s not recommended either. There are many reasons why a three-gallon tank is a bad idea for guppies.

Shorter Lifespan

Guppies are highly active fish who need to swim to stay healthy. A small confined space will considerably restrict their movement.

The slight movement prevents the overall circulation of the blood in the body, which reduces the lifespan of your guppies. That’s why the small tank should only be temporary.

Closeup shot of a guppy fish in an aquarium with green background

Halt of Growth

Pet owners with smaller tanks usually report that their fish don’t grow up to the expected size.

Contrary to common belief, this has nothing to do with the size of the tank but more with how much the fish move inside it.

A smaller tank will restrict the movement and hinder the body’s vital processes. This, in turn, will slow down the growth rate of guppies.

Abnormal Behavior

Guppies are highly friendly fish, but they’re also highly susceptible to anxiety and stress.

A smaller tank would further increase that stress, and you might notice your fish becoming aggressive toward each other.

Furthermore, if you only keep male guppies in the tank, they will compete with each other. The stronger guppies will end up bullying and sometimes hurting the weaker ones.

High Reproduction

If you have at least one male and one female guppy, an already small three-gallon tank will run out of space in no time.

You’d be surprised how fast guppies can reproduce. That’s why it’s recommended to keep the female to male ratio 2:1 or even 3:1.

Bad Maintenance

A small tank will quickly get dirty. Unless you’re dedicated to cleaning it every now and then, the pollution of the tank could be harmful to your guppies.

The more water you have, the less the effect of any bacteria, dirt, or microbes. In turn, this means a healthier tank for your guppies.

For such a small tank to stay clean all the time, you’ll need an excellent filter. Otherwise, you’ll have to clean it every other day if you want to make sure your guppies stay comfortable.

How Many Guppies Can Live In a 3-Gallon Tank?

With everything we’ve mentioned in mind, Guppies should only be kept in a three-gallon tank for a short or temporary period. However, there’s still a maximum number of fish that can live in it.

Male guppies are smaller than females. Therefore, you can keep up to three male guppies in the same tank for short periods.

Of course, you should expect a lot of bullying in that case.

If you have female guppies only, their larger size will restrict you to only two in the tank. But, again, this should only be temporary.

If you have males and females, keep only one of each gender in the three-gallon tank. And hasten their transfer before their reproduction gets out of control.

That being said, the two or three guppies could spend the rest of their lives inside that three-gallon tank. However, their life span would be significantly shortened. We don’t recommend doing that.

How Many Guppies Per Gallon?

Since male guppies are smaller than females, the answer will vary depending on gender.


Theoretically, the minimum requirement for a male guppy should be one-gallon. However, even if you have just one male guppy, the smallest tank you should use is the three-gallon tank.


Again, for one female, the smallest size tank is the three-gallon. However, ideally, you should spare at least a gallon and a half for each female guppy you have. Before you buy the tank or the guppies, do the math to figure out the size you need.

What’s the Ideal Size of a Tank for Guppies?

Guppies are schooling fish, which means they love to move together as one unit. The minimum number of guppies required to have a good social life is three. They should be two males and one female.

The minimum tank size for three guppies is five gallons. You should always go up a gallon or two to make up for the space taken by the filter and anything you add into the aquarium.

Let’s have an example so you can learn how to calculate it yourself.

We have six guppies: four females and two males. That means we need three gallons for the males (one gallon per fish) and six gallons for the females (one and a half gallons per fish.)

That gives us a total of nine gallons. Add one or two for the aquarium substrate and decorations, and the ideal tank size for those seven guppies would be ten or eleven gallons.

Have Another Tank Size You’re Looking for?

How Many Guppies in a 5-Gallon Tank?

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Give Them Space

To summarize things up, you should do your best to give your guppies enough space and freedom to swim in.

Guppies won’t be affected immediately if they live in small tanks, but it will harm them in the long run.

You may be tempted to keep only one guppy in a small tank. This might seem like a good solution, but a single guppy will get lonely.

Guppies are best kept in trios to avoid loneliness. Lonely fish have shorter life spans, and they pass away much earlier than usually expected.

If you have no other option but to use a small tank, then keep your guppies in a three-gallon tank. However, you should get them to a bigger tank as soon as possible.