Do Cardinal Tetras School? The Ultimate Guide

Cardinal Tetras are a relatively common fish that are bright red. Cardinal tetras (Paracheirodon axelrodi) are famous worldwide as Cardinal Tetra, Cardinal Fish, or Cherry Reds and come from South America. They prefer slow-moving waters with lots of leaf litter. Without care, these fish can be challenging to keep alive. Besides this, some owners also assume that it is better to school Cardinal tetras.

So, do Cardinal tetras school? Cardinal Tetras are schooling fish which means that owners can keep them in a school of at least six Cardinal tetras.

If you want your Cardinal tetra to school with other Cardinal tetras, the general rule is the more, the better. You need to have a comfortable environment, proper water conditions, and a good diet for all these fish to survive happily in school.

I will cover some Cardinal Tetra facts in this post and provide a complete guide on how to keep Cardinal Tetras in your home aquarium successfully.

What Is Schooling?

Schooling is a prevalent behavior in fish. Schooling means the process in which fish swim together and stay close to each other throughout an aquarium. This process has many benefits for all types of tropical fish, but it’s crucial for those species who live within groups in nature, such as Tetras & Barbs.

Schooling fish are also calmer and less stressed, which makes them more comfortable in your aquarium. It is a very natural behavior that you can observe among almost all types of tropical fish.

Do Cardinal Teras School?

Many people wonder if cardinal tetras school and the answer is yes. If you do not want them to school, you need to get a group of six or more. Schooling is essential for Cardinal tetras. But you should make sure that the schooling tank has lots of plants and hiding spots.

It will also help if there are other fish around that they can swim with, such as guppies and mollies. Schooling is vital for fish that live in the wild, and they will often school together when it gets dark out so that predators cannot see them easily.

What Are The Benefits Of Keeping Cardinal Tetras In School?

Schooling fish can be very beneficial to both you and the fish. Schooling fish are happier and healthier because they will exercise more than the average non-schooling tetra, which means their immune systems become more robust. As a result, it makes them less likely to contract diseases or parasites such as ich if exposed to it.

Some of the benefits of schooling Cardinal Tetras are:

When You School Cardinal Tetras, They Are less Likely To Be Aggressive

Schooling fish tend to be less aggressive because they have a strong group dynamic and strengthened social structures. In addition, schooling makes them feel safer, so you will find that Cardinal Tetras can coexist more easily with other non-schooling tetra types such as the neon tetra or Glowlight tetra.

When You School Cardinal Tetras, They Are More Likely To Breed

Schooling fish tend to breed more often than non-schooling fish. It is because schooling fish feel safer and less threatened when they are in the presence of their species; this means that if you wanted to start a breeding project with your Cardinal tetra Fish, it would be much easier to do so. Schooling fish are also generally more relaxed and less stressed out, which makes them healthier in general.

When You School Cardinal Tetras, They Are More Likely To Survive

Schooling fish tend to have a longer lifespan than non-schoolers because they feel safer when surrounded by their species. In addition, it means that they are less likely to feel stressed out and, therefore, more able to fight off disease.

Schooling fish also tend to grow faster than non-schoolers because of the increased exercise that their bodies get from schooling. It is an excellent instinct for Cardinal tetras, and it can have many benefits both physically and psychologically for your Cardinal Tetras.

Schooling Cardinal Tetras Develop A Stronger Immune System

Schooling fish are happier and healthier because they will exercise more than the average non-schooling tetra. In addition, it means that their immune systems become stronger as a result.

Schooling Cardinal Tetras Are Less Likely To Contract Disease

Schooling helps protect these fish from developing diseases by strengthening their immune system. As a result, Cardinal tetras can easily fight off any illness or parasites such as ich.

Schooling fish can be very beneficial to both you and the fish. The fish that moves in school are fascinating to watch. You will love to watch these fish swimming and moving around the aquarium.

What Are The Drawbacks Of Keeping Cardinal Tetras In School?

Schooling is an important part of cardinal tetra development. But sometimes, if you fail to manage the proper environment for their schooling behavior. Schooling can light to a lot of issues in your Cardinal tetras. These can include:

  • Schooling in the tank and making it dirty is not suitable for aquatic life
  • Fighting among cardinal tetras
  • One fish starts bullying others when they are alone.

What Are Things to Consider When You School Cardinal Tetras?

To keep Cardinal tetras happy and healthy in the schools, you need to provide them with the following conditions.

Schooling Tank Size

The school tank should be 20 gallons per Cardinal tetra. So, for example, if you want to keep ten Cardinal tetras in your aquarium, then it is best that you get a 200-gallon fish tank. However, do not overstock because too many fish will lead to an ammonia spike, which will be harmful.

Schooling Tank Temperature

The school tank should have a temperature of 22 Celsius degrees (72 Fahrenheit). There is another reason why most owners recommend keeping Cardinal tetras in a large aquarium. It is because they need enough space to swim around.

Thus, schooling fish will require more water which requires a giant aquarium. In addition, keeping many schooling fish in a confined area will result in aggression, fin-nipping, and injuries.

Schooling Tank Cover

Cardinal tetras need a school tank with a cover for their safety and health because they are prone to jumping out of the water. They also tend to jump when they feel startled or frightened. So, when you fail to cover your school tank, it can lead to Cardinal tetra injuries from them jumping out of the tank.

Schooling Food

Feed your cardinal tetras every day with a school food diet because they become weak and sick if they go without food for too long, so you can feed them at least three times per week to keep their health in check.

Schooling fish wants a food very rich in nutrition. Thus, you must feed these fish with enough food. Schooling food is usually in the form of freeze-dried or frozen foods that meet most Cardinal tetras’ nutritional requirements.

Schooling Tank Cleanliness

You have to clean your school tank every day because multiple fish will use it. As a result, they are more likely to make a mess when they eat. So, if you don’t keep up with cleaning, there will be a high concentration of ammonia, which can be very harmful to Cardinal tetras.

Schooling tanks should also have a filter. But it is worth noting that too many filtration systems will weaken the water and put a strain on the fish. Thus, it would help if you found balance when setting up your school tank’s filtration system.

Schooling Tank Decorations

Cardinal tetras need their school tank decorated with plants because they spend most of the time in or near to them, so it’s essential for your fish that you provide enough space and cover with live plants, artificial plants, rocks, caves, etc. It will give your cardinal tetras the best chance to school and hide from potential predators.

Schooling Lighting

Cardinal tetras need a school tank with bright lighting because they are omnivorous fish that eats at night. They will navigate through schools, find food, avoid predators, etc., in the dark. Thus, it is a better idea to keep Cardinal tetras in brighter lighting.

It would help if you lighted schooling tanks with blue or white spectrum because these are the best options to use when schooling fish.

Schooling Water Parameters

The school tank water needs to stay between pH levels of six and seven, so it’s advisable to use water testing kits to monitor the pH levels so you can always have a safe environment for your cardinal tetras. Schooling tanks also need higher oxygen levels because multiple fish require more dissolved oxygen in the tank, particularly when schooling.

How Many Cardinal Tetras Can I Keep In A School?

Cardinal tetras are very peaceful, active, and beautiful creatures. Therefore, you can place them with other calm species of similar size without any issues. However, they do need to swim around in groups instead of staying alone and isolated. It is because they’re highly social animals by nature. Thus, you will need at least five cardinal tetras to form a school.

It would help if you kept schooling fish in groups for their safety because they will feel less scared when around each other. In the wild, cardinal tetras swim in gigantic groups. Most Cardinal tetras owners consider large schools more effective than isolated individuals at deterring predators. It is because they can easily blend into their school’s color pattern while swimming together.


Summing up, Cardinal Tetras are very social fishes, and they will appreciate having other Cardinal Tetras in their tank.

They love to swim, so make sure you have a spacious aquarium with plenty of vertical space for swimming. You can use plants or driftwood as hiding places if there is not enough natural cover in the habitat, but be careful when choosing decorations because they might accidentally break them.

Do you have any questions about Cardinal Tetras School? Please leave a comment in the section below!

Thanks for reading my post. See you soon!​

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