Cardinal Tetra

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Paracheirodon axelrodi - (Schultz, 1956)
Cardinal Tetra

Still mostly collected from the Amazonian wilds, this fish may need careful feeding and conditioning when it is first acquired.


Once known as The Rich Man’s Neon Tetra, the Cardinal Tetra is now a popular schooling aquarium fish commonly imported from the Amazon basin.

The electric-blue-and-impossible-red Cardinal Tetra is somewhat sensitive to water conditions, requiring warm, soft and acidic water to prosper. Their tanks should be well planted on the sides and back, with a layer of floating plants to diffuse the light, and plenty of room to swim in the center.

Buying wild-caught Cardinals is highly recommended by rainforest ecologists: Buy A (Wild) Fish - Save A Tree.

Family: Characidae

Other common name(s):

Native range:

Maximum length: 2.5 cm (1 in)

Minimum aquarium size: 38 L (10 gal)

Water: Freshwater 22 °C (72 °F) - 26 °C (79 °F)

General swimming level: Mid-level.


In recent years, some hobbyists report difficulties acclimating new specimens, which may arrive from the wild malnourished and in less than ideal condition. They can often be restored with a diet of live or frozen black worms, white worms, live (enriched) adult brine shrimp or other high-quality, rich foods.


Omnivore. Its diet in the wild includes various worms and crustaceans. Paracheirodon axelrodi eats absolutely anything in the aquarium — flakes, pellets, freeze-dried and frozen foods, including brine shrimp, black worms and Daphnia. The latter foods can be used to recondition new Cardinals showing any signs of malnourishment.

Aquarium Compatibility

Cardinal Tetras are small schooling fishes that should be kept in groups of at least five or six (the more the better) with other peaceful community tank residents of similar size. Do not trust them with larger fishes, such as Angelfish, that will chase and eat them.


Breeding in the aquarium is difficult, and most aquarium specimens are wild caught.


A dark-colored background and substrate will help to show off the fish’s colors. Decorate with driftwood and rocks.

Reference: 101 Best Tropical Fishes
Image credit: JJ
Text credit: KW