Cardinal Tetra

About the Cardinal Tetra

The Cardinal Tetra is one of the most iconic and sought-after freshwater aquarium fish in the world. Famous for its brilliant electric blue stripe and vibrant crimson-red body, this peaceful schooling fish is native to the blackwater rivers of the Amazon Basin in Brazil, Colombia, and Venezuela. Its dazzling colours and calm temperament make it a favourite for planted aquariums and South American biotope displays.

Often confused with the Neon Tetra, the Cardinal Tetra can be distinguished by its bright red stripe, which extends the full length of its body from the gill plate to the tail. Their colours become even more vibrant against dark substrates, lush aquatic plants, and subdued lighting.

Cardinal Tetras are highly social fish and should always be kept in schools of at least ten, although larger groups create an even more spectacular display. They thrive in mature aquariums with driftwood, leaf litter, gentle water flow, and excellent water quality. Their peaceful nature makes them ideal companions for Angelfish, Discus, Corydoras, Apistogramma, Rams, Pencilfish, Hatchetfish, and other peaceful South American species.

A varied diet of premium micro pellets, quality tropical flakes, frozen bloodworms, baby brine shrimp, daphnia, cyclops, and other small live or frozen foods will help maintain their vivid colours and excellent health.

Elegant, hardy, and breathtaking in large schools, the Cardinal Tetra remains one of the finest choices for freshwater community aquariums.

Quick Care Guide

Scientific Name

Paracheirodon axelrodi

Common Name

Cardinal Tetra

Origin

Amazon Basin (Brazil, Colombia, and Venezuela)

Adult Size

4–5 cm

Temperament

Peaceful

Diet

Omnivore

Minimum Tank Size

60 Litres

Temperature

24–29°C

pH

4.5–7.0

Water Hardness

1–8 dGH

Difficulty

Beginner

Lifespan

4–6 Years

Suitable For

Planted aquariums, blackwater aquariums, South American biotopes, and peaceful community tanks

Frequently Asked Questions

What is the difference between Cardinal Tetras and Neon Tetras?

Cardinal Tetras have a vibrant red stripe that extends the entire length of the body, while Neon Tetras only have red colouring on the rear half. Cardinal Tetras also prefer warmer water, making them excellent companions for Discus and Angelfish.

How many Cardinal Tetras should I keep?

Cardinal Tetras are schooling fish and should always be kept in groups of at least 10. Larger schools of 20 or more create an incredible natural display.

What do Cardinal Tetras eat?

They thrive on premium micro pellets, tropical flakes, frozen baby brine shrimp, bloodworms, daphnia, cyclops, and other small live or frozen foods.

Can Cardinal Tetras live with Discus?

Yes. Cardinal Tetras are one of the best companions for Discus because they enjoy the same warm, soft, acidic water conditions.

Can Cardinal Tetras live with shrimp?

Yes. Adult Cherry Shrimp and Amano Shrimp are generally safe, although newly hatched shrimplets may occasionally be eaten.

Common Mistakes

Keeping them in small schools

Cardinal Tetras become shy and stressed when kept in groups smaller than ten. Larger schools display better colour and more natural behaviour.

Adding them to immature aquariums

They perform best in established aquariums with stable water parameters and excellent filtration.

Poor water quality

Regular water changes and pristine water conditions are essential for maintaining vibrant colours and long-term health.

Feeding only flake food

A varied diet including frozen and live foods promotes better colouration, stronger immune systems, and improved breeding condition.

Housing them with aggressive fish

Choose peaceful tank mates that won't intimidate or prey on these small schooling fish.