Cardinal Tetra: Vibrant Jewels of Freshwater Aquariums [3 MUST Know Tips]

Cardinal tetra (Paracheirodon axelrodi) the most popular ornamental fish for aquatic plants tank. close up photo
Cardinal tetra (Paracheirodon axelrodi) the most popular ornamental fish for aquatic plants tank. close up photo

Cardinal Tetras: The Vibrant Jewels of Freshwater Aquariums


Cardinal Tetras (Paracheirodon axelrodi). Renowned for their vibrant red and blue stripes, these mesmerizing fish add both color and movement to your aquatic paradise. Like the captivating Red Cherry Shrimp, Cardinal Tetras are a delightful choice for hobbyists looking to bring a touch of the wild into their homes.

Cardinal Tetra Quick Reference Table:

Scientific NameParacheirodon axelrodi
SizeUp to 2 inches (5 cm)
Natural HabitatOrinoco and Negro Rivers, South America
Tank Conditions73-81°F (23-27°C), pH 5.5 to 7.5, Soft to Moderate
DietOmnivorous: Flake food, Brine Shrimp, Daphnia
Tank MatesHarlequin Rasboras, Corydoras Catfish, and others
BreedingIn a controlled, well-prepared breeding tank
Cardinal Tetra Quick Reference Guide

Appearance and Size:

Cardinal Tetra

Cardinal Tetras boast a slender, elongated body adorned with striking longitudinal stripes. The bold red stripe runs along the lower body, flanked by a brilliant blue stripe on the upper side. Typically, they reach a size of about 2 inches (5 cm) when fully grown, making them a compact yet eye-catching addition to your aquarium.

Natural Habitat:

Originating from the warm, soft, and slightly acidic waters of the Orinoco and Negro Rivers in South America, Cardinal Tetras thrive in well-planted environments. In the wild, they maneuver through dense vegetation and fallen leaves, a lifestyle that can be replicated in a home aquarium to keep them comfortable and healthy.

Tank Conditions:

To mimic their natural habitat, a tank for Cardinal Tetras should have a temperature range of 73-81°F (23-27°C), a pH of 5.5 to 7.5, and soft to moderately hard water. Plentiful vegetation, a dark substrate, and subdued lighting will help recreate the peaceful and sheltered conditions of their native waters.


Cardinal Tetras are omnivorous by nature, feeding on a balanced diet of small insects, crustaceans, and plant matter in the wild. In the home aquarium, they will thrive on high-quality flake food, brine shrimp, and daphnia. Occasional treats of live or frozen foods will keep them in vibrant health.

Tank Mates:

Much like the peaceful coexistence of Red Cherry Shrimp with other tank mates, Cardinal Tetras are community-friendly fish. They get along well with other peaceful and similarly sized fish such as Harlequin Rasboras, Corydoras Catfish, and of course, the Red Cherry Shrimp. Their tranquil demeanor makes them a harmonious choice for a community aquarium.


Breeding Cardinal Tetras can be a rewarding experience for the dedicated hobbyist. With a well-prepared breeding tank mimicking their natural conditions, these tetras will spawn, laying their eggs among fine-leaved plants. Patience and a controlled environment are keys to successfully breeding and raising the fry.

3 Must-Know Tips for Keeping Cardinal Tetras

  1. Proper Acclimatization:
    • Cardinal Tetras are sensitive to water changes, and proper acclimatization is crucial when introducing them to your aquarium. A slow drip acclimatization over an hour or two will help ease them into the new water conditions, reducing stress and promoting a healthier transition.
  2. Maintaining Good Water Quality:
    • These vibrant fish thrive in clean, well-filtered water. Regular water changes, at least once a week, and a good filtration system are essential to keep the water parameters stable. Testing the water for pH, hardness, and the presence of ammonia, nitrites, and nitrates will ensure it remains a conducive environment for your fish.
  3. Schooling Nature:
    • Cardinal Tetras are schooling fish, which means they prefer to swim in groups. A school of at least 6 to 10 individuals will help them feel secure and exhibit natural behaviors. The sight of a shimmering school of Cardinal Tetras darting through the aquatic foliage is a captivating display and a hallmark of a well-maintained community aquarium.

By adhering to these tips, you can ensure a happy, healthy, and visually stunning habitat for your Cardinal Tetras, making your aquascaping endeavor a rewarding experience.


Cardinal Tetras are a captivating choice for any freshwater aquascaper. Their vivid coloring, peaceful nature, and ease of care make them a popular choice among hobbyists. Whether you’re a seasoned aquarist or just embarking on your aquatic journey, the Cardinal Tetra is sure to bring a splash of color and life to your underwater garden.

Chad Latta
Chad Latta

I have over 20 years in the aquarium hobby! My love for writing and passion for helping people have led me to bring you the most effective and up to date information possible, in a way that is easy to understand. Enjoy!