How Many Neon Tetras in a School? {What Happens When There Aren’t Enough?}

Are you looking to keep a few neon tetras and want to know how many neon tetras in a school?

Do Neon Tetra school? Should they be kept alone?

Find out below

How Many Neon Tetras in a School?

4-6 Neon Tetras in a minimum 10 gallon tank will school together for comfort, safety and calm interaction. Any less may result in bullying, excessive hiding, lethargy and lack of appetite. It’s better to keep up to 10 Neon Tetras in a 20 gallon tank.

How Many Fish Can You Have in a Neon Tetra School?

While you will commonly find information that leads you to believe that four to six neon tetras in a 10 gallon tank will suffice, we recommend the more the merrier.

That is to say, you will need a 20 gallon tank for up to 10 neon tetras to school together in peace. 3 neon tetras may lead to the larger of one harassing one of the two remaining neon tetras.

It will be challenging for only three of them to school together.

Will Different Tetras School Together?

It isn’t a guarantee that you can place different tetra species in a tank and expect them to school and swim together.

There are conditions that may lead an individual tetra of one species to join the school of another. Here are a few that we have outlined below:

  • 4-6 members of each tetra species may join an equal number of another tetra species.
  • A single lonely tetra that is similar in size, color and behavior may join the school of tetras of another species.

An example of two types of tetras that may join up in one school are the neon tetras and cardinal tetras.

Their behaviors and size are similar to each other and one may accept the other to join in a school for protection, safety and overall calm behavior to reduce stress in a community tank.

Are Neon Tetras Schooling Fish?

Yes. Neon tetras are schooling fish that love to swim together. They will only do this if you keep enough of them together in the same tank.

While the minimum number you may find is 4, we recommend at least 6 and closer to 10 to achieve a comfortable and peaceful school of neon tetras.

The behavior that you would like to promote is for your neon tetras to naturally swim laterally across the entire distance of your tank.

You want to eliminate excessive hiding that results from shy or timid neon tetras that feel uncomfortable when they are unable to school together.

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Can I Have 3 Neon Tetras?

There is a debate that neon tetras can be kept without being placed in a school as long as you have plenty of space and hiding locations in a heavily planted tank with lots of decorations.

We tend to disagree because if you keep neon tetras in a group of three, they may not school together and could feel uncomfortable.

The hiding spaces would be nice, but they may never come out. Another factor is that a larger neon tetra may pick on another of its species especially if they never get the opportunity to school together.

A bullied neon tetra may:

  • give up eating
  • lose its color
  • sulk in corners
  • become susceptible to illness
  • have its growth stunted
  • die suddenly

Can Neon Tetras Live With A Betta?

If you would like your neon tetras to coexist peacefully in the same tank with a betta fish you are going to need to take on a few precautions:

  1. Remember to keep 1 inch of fish per gallon of water.
  2. Keep 4-6 or up to 10 Neon Tetras.
  3. Each Neon Tetra could reach near 2 inches.
  4. A Betta may also reach 2-3 inches.
  5. The Betta would prefer to be kept away from other Bettas.
  6. A 20-30 gallon tank would be the minimum size required.
  7. Hiding spaces with decorations and plants are needed for added comfort.
  8. Feed them in separate corners or use temporary tank dividers if there is competition for food.

What Is a Good Size Tank for Neon Tetras?

A 20-gallon tank is the best tank size for keeping the smallest school of neon tetras which is about 4-6 of them at the same time.

The reason being is that these fish love to swim in a horizontal pattern and 10 gallons may not give them enough room to enjoy themselves.

At this point, if you notice your neon tetras enjoying a peaceful life together, you may consider it time to add a few more.

With a 20 gallon tank you’re able to add up to 10 neon tetras total since they are considered nano fish that grow an average of 1.5 inches.

Are Neon Tetras the Smallest Aquarium Fish?

No. The neon tetra is considered to be a micro or nano sized fish that grows up to 1.5-2 inches.

The honor of the smallest aquarium fish goes to the Indonesian Super Dwarf Fish measuring at 0.41 inches in length.

How Many Green Neon Tetras Can I Keep in a School?

You would ideally like to keep a minimum of 4-6 green neon tetras that are considered micro or nano size fish.

They are extremely peaceful and beautiful in appearance with blue green patterns and a lateral streak that makes them stand out in your aquarium. Neon Tetra disease is a common ailment for any type of fish in this species.

Therefore, it is best to keep them in a quarantine tank for up to two weeks to ensure that this contagious disease never gets the chance to inflict any damage on the rest of your aquatic life in your community tank.


If you have come here to find out how many neon tetras you should keep in a school, we hope that we have done the best we could today to explain it to you.

The common response you’re going to find is that 4 to 6 neon tetras can school together comfortably in a community tank or on their own in a 10 gallon tank. We recommend keeping up to 10 neon tetras together in a 20 gallon tank or larger.


Thank you for visiting for all your informational needs regarding any of the Aquatic Life that you are interested in keeping in your aquarium. See you again soon!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.