Are Cardinal Tetras Schooling Fish?

Since keeping fish is more accessible in comparison to other pets, most people keep fish at home. However, with the increasing popularity of fish-keeping culture, nowadays aquarists are showing interest in varieties of fish. Among them, the schooling behavior of Cardinal tetras makes this fish a bit more interesting for beginner aquarists to keep.

Are Cardinal Tetras Schooling Fish? Yes, indeed. Cardinal tetras are schooling fish. They follow each other all the time. Usually, these fish enjoy being together, sharing a tank space with their fellow schoolmates, or swimming in synchronized movement. And, if one fish somehow separates from its school, this poor little guy feels confused and lost because it cannot find its schoolmates.

Schooling behavior is a fascinating topic to talk about. But, there are a lot more things that you need to know about cardinal tetras. In this article, I will try to cover all the information related to cardinal tetras. So, let’s start!

What Are Schooling Fish?

Schooling fish are those that live in groups. There is safety in numbers, so schooling allows better protection against predators and tremendous success when hunting prey. However, schools of fish can also confuse their predator by giving the appearance of more than one target or multiple targets to choose from.

This high level of coordination between members within a school requires a lot of communication. They have a wide variety of ways to communicate, from sending electrical signals to emitting pheromones.

Are Cardinal Tetras Schooling Fish?

The short answer to this question is yes. Cardinal tetras are schooling fish and will do so throughout their lives.

Cardinal Tetra school in the wild, and they do so for protection. Schooling helps protect them from predators by making it difficult to single out one fish in the group. It also allows them to move around together in a synchronized manner, making it easier for each individual to find food.

It is possible for them to school in an aquarium setting, but it will take more work on the fish keeper. Keeping them in a larger school may be necessary to allow them enough space to swim together without feeling threatened or stressed out.

Even though cardinal tetras are schooling fish, they may start with difficulties when you first get them in your tank. Usually, this is because the water conditions in tanks are often different from those of their natural habitat. So, it can take a while for new fish to acclimate accordingly. Once they have adjusted to the changes in their environment, though, they should happily school with each other.

What Is The Ideal School Size For Cardinal Tetras?

While it may be nice to have a school of 20 or more cardinal tetras unless you have a vast aquarium, this will probably not happen. In reality, even for the most miniature home aquariums, I would recommend no less than six cardinal tetras. This size group will provide some sense of security, and the fish will be able to establish their hierarchy. While dominance fights may break out, this is normal and will not cause any harm to the fish.

Cardinal tetras are schooling fish that do best in at least six or more groups if you have a large enough aquarium. If you only plan on having less than six cardinal tetras for your community tank, it’s essential to make sure they are the only fish in that tank.

What Are The Benefits Of Schooling Cardinal Tetras?

Although schooling behavior seems a little unfamiliar term for new fish keepers, for experienced hobbyists, the behavior is not surprising. Moreover, since schooling has remarkable benefits for each fish, anybody interested in keeping cardinal tetras should strongly consider it.

However, some of the advantages of schooling cardinal tetras are:

Better Survival Rates During Stressful And New Experiences:

When cardinal tetras live in a school, they feel safe. And that is great for overcoming any stress or fear factor. Fish release lots of chemicals under stress which can be lethal to their kind. While fish living in schools secrete fewer amounts of these chemicals.

Schooling fish has fewer reasons to feel stressed and release chemicals. Usually, they are much more likely to survive through any new experiences.

The Stronger Immunity And Better Disease Resistance:

On their own, cardinal tetras are very susceptible to different diseases and parasites because of limited resources for dealing with them. However, when living together in a school where each fish gets its share of benefits, the group becomes more resistant to different illnesses.

A Better Chance Of Moving Through Food Chains:

Cardinal tetras are omnivorous fish that eat both plant-based and meaty foods. That means they can quickly move up food chains, giving them a significant advantage for surviving in any environment. And that is especially true for places where fish populations are low, and other omnivorous species take over the territory.

Increase The Breeding Chance:

When cardinal tetras live in a school, they feel pretty safe. It is crucial when it comes to breeding. The fish have significantly better chances of becoming parents if they live together in schools rather than being alone or staying with other individuals from their species.

Schooling Cardinal Tetras Are Less Aggressive:

Aggressive behavior in cardinal tetras usually occurs when there are not enough hiding places. And that is especially true for the ones on the lower end of food chains. However, since schooling requires more space than solitary living does, each school member gets their place to hide and relax after meals or during stressful times of their life cycle. This way, schooling cardinal tetras are much friendlier towards each other.

Cardinal tetras benefit from all things as long as they live in a school with their kind. Furthermore, it would be best to encourage such behavior because it means much better chances of survival for each fish.

What Are The Disadvantages Of Schooling Cardinal Tetras?

There are a few disadvantages of keeping cardinal tetra fish in schools or groups throughout their life cycle. And the most common ones are:

The Tanks Are More Likely To Get Dirty

Cardinal tetras are very active fish, and they produce a lot of waste. So, it might make the tank get dirty faster. As a result, this makes it necessary to clean it more frequently. Their activity level also influences how often you need to feed them because their metabolism is just as high.

A Lot Of Fish In One Tank Means More Aggressions

Cardinal tetras are very peaceful fish, and it is not common to see them fight among each other. However, they might become more aggressive when in a group of their kind. It means that if you plan on keeping only cardinal tetra in your tank, then make sure you have a large one because otherwise, the aggression level will increase.


When kept in a group, cardinal tetras can be very aggressive towards each other. It is especially the case when you place only two or three cardinals together. In this situation, they might start bullying one of their kind. Thus, it will result in injuries if you do not stop them from fighting continuously.

Need More Food

Cardinal tetras are not very picky eaters, and they will gladly accept most types of food. However, with so many fish in a tank, it might be harder to feed them all at the same time because there is never enough food for everybody. It means that you need more filtration or an extra feeding plate if you keep your cardinals in a group.

Difficult To Manage Breeding

Cardinal tetras are easy to breed in a group of their kind if they have the right conditions. However, it is challenging to manage breeding when keeping them in groups because cardinals tend to show sexual aggression towards each other during spawning, making caring for eggs harder than usual.

What Should You Do To Keep Cardinal Tetras Safe And Healthy In Schools?

Keeping Cardinal tetras safe and healthy in schools can be a challenge. Therefore, it would be best if you continued to research the right resource of information that will help you keep your Cardinals alive and well for as long as possible.

Usually, the best tips for keeping these schooling fish alive and well are:

Use A Proper Tank Size For Schooling Cardinal Tetras

Cardinal tetras are a tropical fish species that require the right tank size to live successfully. However, just because they come from slow-moving waters in South America does not mean they need small, cramped tanks.

It would be best if you planned on having at least 20 gallons tank for them to thrive long-term. It will allow room for some of their schools to spread out, and less competition will be. Keeping them in small tanks can cause aggression between the fish because they are trying so hard not to bump into each other all of the time.

Provide Healthy Food For Schooling Cardinal Tetras

Cardinal tetras are omnivores, which means they eat both plants and meat. They love to eat live plants like algae or any sinking plant matter (or even some floating). You can feed them flakes, but make sure you get high-quality flake food with lots of protein. It will help them grow to their full potential.

If you are giving your fish sinking pellets, make sure that they are small enough for the fish to eat quickly, or else it can create issues with digestion. Also, be aware of any foods containing fat because excess amounts can cause problems in these already sensitive little fish.

Cardinal Tetras Need Good Water Quality

It is the most crucial factor for keeping any fish species alive and healthy. You will want to make sure that you have a good filter on your tank, along with regular weekly water changes of at least 50%. It will keep ammonia levels down so they do not get sick from it.

It is also helpful if there are multiple filtration systems in your tank, such as filters and bio-balls for nitrifying bacteria. And also, will help keep the water clean even if you do not change all of it.

Maintain Suitable Water Parameters For Schooling Cardinal Tetras:

When you see more than one school of cardinal tetra, it is crucial to maintain their ideal water parameters. Otherwise, the fish might become ill due to different pH or hardness levels in each tank. The perfect temperature range for these fish is between 68 and 82 degrees Fahrenheit, with a pH level ranging from five to eight. Avoid keeping them in overly acidic or alkaline water conditions, as this will cause the cardinal tetras to stress and even lead to death.

Use Proper Lighting For Schooling Cardinal Tetras

Cardinal tetras are a very colorful fish species, and they will display their best colors when there is proper lighting in the tank. You should make sure that you have some sort of light source in your aquarium for at least nine to 12 hours daily. Fluorescent bulbs work well because they emit less heat than incandescent lights.

Cover The Tank

When you keep too many Cardinal tetras in the tank, they are more likely to jump out. Keeping them in a covered aquarium will help prevent this from happening, especially if you put some lid on top that is not too heavy for them to swim through.

Do Not Mix Different Cardinal Tetra Species In One Tank

Cardinal tetras are very social fish and love to interact with their species when it comes time for mating, so if you mix different types of cardinal tetras in one tank, they will not be happy. As a result, the best coloration may never develop in your school. Therefore, choose the tankmates for Cardinal tetras very carefully to ensure it is the best possible community for them.

Place Some Plants And Vegetation In Their Tank

Cardinal tetras love to swim around in planted aquariums, and they will enjoy a tank that has some live plants and artificial ones. The live plants provide food for them while also giving their environment a more natural feel. If you do not have any real plants, make sure your fake ones are heavy on the root systems because cardinal tetras love to eat them.

Keep Decorations To Entertain Schooling Cardinal Tetras

Cardinal tetras like to swim around and play, so make sure you have some decorations for your tank. It can be anything from big rocks on the bottom of the tank or even large pieces of driftwood! The more natural it looks, the better because they are familiar with living in a rainforest, an environment with lots of large trees and fallen leaves.


What Is The Schooling Behavior Of Cardinal Tetras?

Cardinal tetras are very active fish. They tend to dart around the aquarium, and some people think that they’re always on the go. However, you will find that cardinal tetra school together often to feel safe from predators or other dangers of the aquarium.

Do Cardinal Tetras School When They’re In A Safe Environments?

Cardinal tetra school because they want to feel safe, which may not mean that the fish are in a dangerous environment. However, if you have an open-top tank, cardinal tetras can jump out of your aquarium, so you should always keep a lid on your aquarium.


Lastly, schooling behavior is an exciting aspect of Cardinal Tetras.

Even though they are relatively easy to care for once acclimated properly, their schooling behavior makes this type of tetra difficult for beginning aquarists who are just starting with a fish tank.

Cardinal tetras can be sensitive to their environment. So aquarists need to make sure that they have access to clean water and the appropriate conditions to thrive.