Cardinal Tetra Fish Care: Size, Lifespan, Tank Mates, Breeding & More

cardinal tetra care guide

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Whether you’re a beginner or not, cardinal tetra can be one of the best aquarium species you can get. They are easy to keep, tough, and extremely beautiful. This fish can be excellent for a community tank as their vibrant colors can be pretty to look at.

Yet caring for them can be a bit different than caring for other similar fish species. That is not to say it’s impossible!

In this care guide, you’ll find out everything you need to know about keeping cardinal tetras. From their habitat, diet, and suitable tank mates, to breeding and appearance.

Let’s get straight into it!

Scientific Name:Paracheirodon axelrodi
Common Names:Cardinal tetra, red neon, large neon tetra & roter neon
Care Level:Easy (Beginner Friendly)
Size:Up to 2 inches
Color:Red and Blue
Life Expectancy:Up to 5 years
Tank Size:Minimum 20 Gallons
Tank Setup:Requires open swimming space


cardinal tetra tank setup

Paracheirodon axelrodi is a popular freshwater species that can fit in most tanks. Aquarists love them for their bright colors and relatively easy maintenance. Did you know some people call them Red Neon Tetra because they’re very similar to Neon Tetras? More on that later!

This species can be found in the wilderness of South American rivers, although they are also bred in captivity. Nowadays, you can buy them for just $2 in most aquarium stores, thanks to their booming popularity.

Cardinal Tetra fish has a lifespan of around five years if they’re healthy and live in a clean aquarium.

Best of all, this fish can adapt to a wide range of tank conditions, which means they are ideal to introduce into community tanks and for beginners!

Typical Behavior

You will notice that Cardinal Tetras love shoaling and live in groups. So, it’s best to keep them in large groups as they can swim around both the middle and upper parts of an aquarium.

As long as the tank is large enough for them, the more of them are together, the better.

It is because this fish feels more comfortable when surrounded by their kind. Keeping them alone or only in pairs can be detrimental to their health as they become stressed. Plus, they become easily intimidated by other aggressive fishes.

Generally, this species is very peaceful. You can keep them in a community or species-only tank.


A Cardinal Tetra’s size can reach only 2 inches in length, even when they are fully grown.

Most people get this fish because of their bright and striking colors, which are usually red and blue. They have red and blue stripes running from the head to the tip of the tail.

The blue stripe can catch light and shimmer, giving it a sparkling finish that glows under some light. Meanwhile, the bright red strip blends into the transparent tail.

You can differentiate the male and female fishes, although they do look quite similar. Females have a rounder body, especially when it’s close to breeding season.

That said, you can simply keep both sexes together so you won’t have to tell them apart.

Cardinal Tetra vs Neon Tetra

cardinal tetra vs neon tetra
Cardinal Tetra vs Neon Tetra

A lot of people think these two species are the same because they have the same colors. But don’t mistake them for each other!

Cardinal Tetra’s red stripe spans the entire body length, while Neon Tetras only have red stripes that run halfway. Meanwhile, the latter’s blue band has a duller coloration.

Cardinal Tetra Tank Setup

In the wild, these fish flock to flooded forest regions and large rivers. Their habitat typically have plants and rocks near the bottom of the water, but there are still plenty of space to swim around.

While some of these water bodies are bright and well-lit, others are dark and more shaded. Meanwhile, the water is warm and a little bit acidic, without any fast currents or movements.

If you understand the natural habit of this species, you can create the perfect home for them!

Conditions and Requirements

When setting up your tank, you can use any substrate as this fish don’t tend to swim near the bottom anyway. Consider fine sand if there are bottom-dwellers in the tank, as this will help prevent scratches and injuries.

We recommend placing some live plants to provide shelter for the fish (read: The 10 best freshwater aquarium plants for carpeting). Cardinal Tetra likes to hide in nooks like these when they feel threatened or stressed. Consider Anubias Nana or Java Ferns, for instance.

There should be enough open space for swimming.

In terms of the water, the temperature should be around 73 to 81°F with a pH of 6 or 7. There’s no need to create massive water movements and regular lights should be ample for them.

Tank Size

Remember that they love swimming around a tank and shoaling. This means you should provide them a large tank that can accommodate at least six of them. For this number, you would need a 20-gallon tank.

When adding more Tetras, make sure to have two extra gallons per fish.

It’s important to ensure there’s plenty of swimming space as this will keep your Cardinal Tetras happy and healthy, so they can lead a longer life.

Tank Mates

cardinal tetra tank mates

As we’ve mentioned, this fish is amiable and peaceful, which means they can get along with most other peaceful species.

You can keep Cardinal Tetra with fishes like Neon Tetras, Zebra Danios, Mollies, and Guppies. Angelfish and Dwarf Gouramis would be great tank mates too.

It’s a good idea to keep them with bottom-dwellers like Zebra Loaches, as this will fill your tank and provide activities in all areas of the water.

For non-fish tank mates, consider Cherry Shrimps and Mystery Snails!

However, try to avoid territorial species like Rainbow Shark. They are very aggressive and will bully your little fish.

Keeping Multiple Cardinal Tetras Together

Unlike some species that do better when alone, Cardinal Tetras thrive in a group. This is because they enjoy shoaling. In fact, the more fishes are living together, the better it is!

We recommend having at least a group of six.

Cardinal Tetra Care Guide

cardinal tetra tank requirements

Most beginners should be able to care for this fish, as they are not demanding and can survive in most water setups.

Of course, they can still get sick like most living things. You need to make sure they have the right nutrients or their colors may fade and become dull. A common disease is Neon Tetra Disease (NTD), which can cause loss in coloration, cysts, and infections.

Look out for other diseases such as ich, bloat, and rotting fin. These are some common aquarium diseases and should be quite easy to handle.

Their immune system can be compromised when they feel weak or when there are sudden environmental changes, including temperature drops.

As long as you keep the tank clean and stable, your fish will be healthy and strong. Don’t forget to change the water regularly and remove any algae build up!

Feeding Your Fish

More good news: Cardinal Tetra will eat anything, including plants and meat.

The best thing you can do is mix their diet to include a variety of food sources, which will ensure balanced nutrients.

Dried foods are easy and convenient, although they can be less nutritious than live or frozen foods. It’s okay to occasionally feed your fish with this, but remember to supplement it with fresh foods.

Furthermore, you can give them some vegetables. Just cut them into tiny pieces and sprinkle them in the tank.

You should feed your fish twice every day in a two-minute block. Remove any uneaten food to prevent diseases and harmful bacteria from developing.

Cardinal Tetra Breeding Guide

It’s natural for this fish to breed in shaded areas. While home breeding has been a challenge for most hobbyists, it’s still feasible. Pay attention to the conditions so you can encourage spawning.

First, set up a breeding tank with low lights and stable parameters. Fry can be sensitive to striking lights, so a darker environment will be better for them.

Choose a pair of healthy fish and supplement them with a healthy diet. When a female fish is carrying eggs, her body will be round and she’ll let a male companion swim with her as she lay the eggs among the plants.

A female Tetra can distribute up to 500 eggs in one time. Also, most of this species usually breed later in the day.

Once the female has laid her eggs, immediately take out the adult fishes. Otherwise, they will eat the eggs and fry.

These eggs will hatch in 24 hours, and the resulting babies will eat the egg sac. It will sustain them for five days as they get ready to swim around.

After that, you can feed them baby brine shrimp and infusoria. Once these baby fishes mature and reach an adult’s size in three months, you can move them to the regular tank. They are now ready to join the others!

Should You Get Cardinal Tetra (Conclusion)?

At the end of the day, we believe this fish is the perfect choice for most beginning hobbyists.

They are hardy, friendly, and easy to maintain. As long as you are well informed and know how to care for them, your Cardinal Tetra will be healthy for a long time.

It’s easy to feed them, and you might even want to try breeding them to multiply your fish population!

Additionally, having a shoaling species can liven up your tank. There’s nothing more interesting than watching a group of fishes swim around together, especially if they have bright colors and beautiful stripes.

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