How Many Neon Tetras in a 55-Gallon Tank?

A 55-gallon tank is big enough to support between 28 and 50 neon tetras at a time. This number of fish will create a healthy community because they love to live in groups of their own kind. 

Neon tetras are popular fish because they’re hardy, peaceful, and don’t require much maintenance. However, if you’re thinking about getting pet fish, you should understand that these fish aren’t able to survive when you keep only one neon tetra in the tank.

So, keep reading to learn more about the ideal number of fish to add to a 55-gallon tank and how to create the right environment for these beautiful creatures.

How Many Neon Tetras in a 55-Gallon Tank?

When you’re thinking about the number of fish to add to a tank, you shouldn’t just think about the size of the fish.

Neon tetras are small fish that usually reach a maximum length of 1.5 inches as adults. However, these small fish need plenty of vertical and horizontal space to swim, so you shouldn’t keep them in a small tank, or it will be too crowded.

The ideal number of fish to keep in a 55-gallon tank is between 28 and 50 fish. However, keeping 50 fish means that they would slightly struggle to swim and live comfortably, and you might be able to witness some aggression, especially during the mating season.

Group of Neon Tetra

How to Estimate the Tank Size for Neon Tetras?

There are several factors that affect the ideal tank size for your neon tetras. Paying attention to these factors guarantees that your fish will be able to survive happily and healthily in the tank.


The bioload in the tank refers to the waste from fish, uneaten food, plant matter, and other living microorganisms in your aquarium.

Anything that lives and breathes in the tank will add to its bioload. Unfortunately, when the bioload is too high, your fish can get sick or even die.

New water enters the fish’s habitat in their natural home, but this doesn’t happen when you keep fish in a tank.

Luckily, neon tetras are small fish and have a small bioload, so you won’t worry much about changing the water in the tank. As long as you don’t overfeed your fish, a 55-gallon tank with 25% weekly changes will be good enough to support your neon tetras.

Swimming Space

Neon tetras are shoaling fish that love to stay together and engage in schooling behavior when some of them move in the same direction. This is why these fish will struggle when you keep them in a small tank.

Despite the small size of neon tetras, you should make sure that the tank is big enough to accommodate all members. Aggression will increase in the tank when the tank is too small, and your fish will become too stressed.

Things will even be more challenging if you’re keeping neon tetras with other fish in the tank. So, you shouldn’t assume that you can get away with a small tank just because these fish are rather small.

What is the Best Tank Size for Your Neon Tetras?

Deciding on the perfect tank size for your neon tetras should be done according to a mathematical rule. This rule states that if the fish measures less than 3 inches long, you should provide it with at least one gallon of water per inch of body length.

So, according to this rule, if you have five fish in the tank, and each one of them measures 2 inches, then a 10-gallon tank would be ideal. However, this isn’t true.

A 10-gallon tank would be big enough for five fish, each measuring 2 inches long, if there’s nothing else in the tank. All the decorative pieces, plants, rocks, sponges, driftwood, and even the filter will take up some space, leaving your fish with no room to roam and swim freely.

Neon tetras measure about 1.5 inches when they reach adulthood, so a 10-gallon tank would leave a little bit of extra space if you decide to keep six fish together. Since the minimum number of neon tetras should be six fish in a group to help these creatures survive, a 10-gallon tank is the smallest tank size you can pick.

For six neon tetras, you need at least a 15-gallon tank to allow the fish to swim freely. These energetic fish will appreciate the extra space, and there will be enough room for all members of the community to live in harmony.

Is a 55-Gallon Tank a Good Choice for 28 Neon Tetras?

If you go with the minimum number suggested of 28 neon tetras in your 55-gallon tank, your fish will have a suitable home that allows them to thrive happily. Here are the pros of housing 28 neon tetras in a 55-gallon tank.

  • This tank is suitable for most spaces, and it won’t break your budget.
  • The tank provides enough horizontal space for all the fish to swim peacefully.
  • A big tank allows the fish to develop properly. They can develop spinal deformities if they’re growing in a tank that is too small.
  • Since neon tetras are mid-level feeders, the extra height in the tank will be suitable for these fish.
  • There will be enough room to add plants and other decorative pieces without crowding the tank.
  • You’d easily notice if one of the fish is sick.
  • Living in a small tank can shorten the fish’s life span, so living in this big tank will be ideal.
  • A bigger tank is more suitable for beginner aquarists because there’s some room for mistakes either in setting up or maintaining the tank.

Have Another Tank Size You’re Looking At?

How Many Neon Tetras in a 29 Gallon Tank?

How Many Neon Tetras in a 20-Gallon Tank?

How Many Neon Tetras in a 10 Gallon Tank?

Wrap Up

A 55-gallon tank is big enough to accommodate between 28 and 50 neon tetras at the same time. However, the more space you provide these fish, the better.

Neon tetras need plenty of horizontal and vertical space to thrive. You should also allow for extra room for live plants and decorations that you’ll add to the tank.