The Cardinal Tetra is a true classic in the freshwater aquarium hobby, known for its brilliant, uninterrupted red stripe and vibrant blue sheen. Native to the blackwater rivers of South America, especially the Rio Negro and Orinoco basins, this peaceful schooling fish brings movement and stunning colour to any well-planted tank. While often compared to the Neon Tetra, Cardinals are slightly larger and offer more intense coloration along the entire body.
Product Details
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Species: Paracheirodon axelrodi
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Common Names: Cardinal Tetra
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Origin: Brazil, Venezuela, Colombia
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Light Requirements: Low to moderate (best under subdued lighting)
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Diet: Omnivorous – Micro-pellets, crushed flakes, baby brine shrimp, daphnia
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Maximum Size: 5 cm
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Temperament: Peaceful, schooling
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Care Level: Easy
Aquarium Setup
Cardinal Tetras thrive in densely planted tanks with soft, acidic water and subdued lighting. A dark substrate helps bring out their colours, while driftwood and leaf litter help recreate their natural blackwater habitat. They feel safest in large schools—aim for groups of 6 or more, ideally 10+, to promote natural schooling behaviour and reduce stress.
Tanks should be well-filtered with gentle flow. Cardinals are best kept in mature aquariums with stable conditions.
Water Parameters
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Temperature: 24°C – 28°C
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pH: 5.5 – 7.0
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Hardness: 1 – 6 dGH
Growth and Maintenance
Cardinal Tetras are hardy once established and adapt well to a home aquarium, provided water quality remains high. They are sensitive to sudden changes, so consistent parameters and regular water changes are key.
Though they are small, their dietary needs should not be overlooked—offer small, high-quality foods such as micro pellets, crushed flake, and live or frozen options like brine shrimp and daphnia to support their colour and health.
Care Tips
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Keep in schools of 6 or more
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Use plants and driftwood to create a natural, shaded environment
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Perform regular water changes to maintain pristine conditions
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Introduce only into mature tanks with stable parameters
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Avoid sudden changes in temperature or pH
Compatibility
Cardinal Tetras are peaceful and best suited to calm community aquariums. Ideal tank mates include:
Avoid keeping them with fin-nippers or large, predatory fish.
Availability
Cardinal Tetras (Paracheirodon axelrodi) are regularly available at Cradle Coast Pet & Aquarium. Get in touch to check current stock and bring home one of the most vibrant, peaceful schooling fish in the hobby.
Disclaimer: Due to natural variation and the age of fish, your Cardinal Tetra may not look identical to the image provided.
