Cardinal Tetra - Paracheirodon axelrodi

Cardinal Tetra (Paracheirodon axelrodi)

The Cardinal Tetra is one of the most iconic freshwater aquarium fish, loved for its brilliant electric-blue stripe and vivid red lower body that runs almost the full length of the fish. It is often compared with the Neon Tetra, but the Cardinal Tetra usually has a more intense full-length red stripe and tends to prefer slightly warmer, softer and more acidic conditions. In a mature planted aquarium, a good shoal of Cardinal Tetras creates a stunning flash of colour through the mid-water area.

Common Name:
Cardinal Tetra. Also commonly referred to as the Red Neon Tetra, Cardinal Fish or Cardinal Neon Tetra.

Scientific Name (Latin):
Paracheirodon axelrodi

Maximum Size:
Around 3–5 cm in captivity, making it a small, colourful shoaling tetra.

Water Type:
Freshwater

Origin / Natural Habitat:
Native to South America, especially the upper Rio Negro and Orinoco river systems across Brazil, Colombia and Venezuela. In the wild, Cardinal Tetras are typically found in shaded blackwater and clearwater tributaries, slow-moving forest streams, flooded forest margins and areas with leaf litter, submerged roots and tannin-stained water.

Water Parameters:
Temperature: 24–28°C
pH Range: 4.5–7.0
Hardness: soft water preferred, although captive-kept specimens can adapt to slightly broader conditions if changes are gradual and stable

Temperament:
Very peaceful and social. Cardinal Tetras are best kept with other small, calm community fish and should not be housed with large, aggressive or predatory species that may stress or eat them.

Diet:
Omnivorous micro-feeder. In nature, they feed on tiny crustaceans, worms, insect larvae and other small invertebrates. In the aquarium they should be offered quality fine flake, micro pellets, crushed granules, frozen daphnia, cyclops, baby brineshrimp and occasional small live foods.

Minimum Tank Size:
A practical recommendation is at least 60 litres for a proper group, with a longer aquarium preferred for a larger shoal and more natural swimming behaviour.

Behaviour & Activity:
This is a peaceful mid-water shoaling fish that should be kept in a group of at least 8, ideally 10 or more. In larger groups, Cardinal Tetras become more confident, colourful and natural in behaviour. They look especially impressive in planted aquariums with darker substrate, subdued lighting, floating plants, driftwood, leaf litter and open swimming space.

Aquarium Category:
Community Fish
This species is ideal for peaceful planted community aquariums with small tank mates such as rasboras, pencilfish, dwarf Corydoras, Otocinclus, small peaceful gouramis, dwarf cichlids and other calm tetras. Avoid large angelfish, predatory fish, aggressive cichlids, fin nippers and any fish large enough to swallow them.

Special Requirements or Care Notes:
Best kept in a mature, stable aquarium with soft water, gentle filtration and regular maintenance. Cardinal Tetras can be sensitive to sudden changes in water chemistry and should not be added to brand-new or unstable aquariums. They are commonly confused with Neon Tetras, but Cardinal Tetras have a red stripe that usually runs almost the full length of the body, while Neon Tetras have red mainly on the rear half.

Suitable for:
Beginner to intermediate fishkeepers

Availability:
Common in trade, with both wild-caught and captive-bred specimens available depending on supplier

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.