Cardinal Tetra
The Cardinal Tetra (Paracheirodon axelrodi) is one of the most iconic and striking freshwater community fish. Known for its brilliant, full-length red stripe and neon-blue upper line, the Cardinal Tetra brings vibrant color and graceful schooling behavior to planted aquariums. Peaceful, small, and visually stunning, this species thrives in stable, well-maintained community tanks. Ideal for aquascapes and nano to mid-sized aquariums, Cardinal Tetras are a top choice for hobbyists seeking elegance and movement.
Care Sheet – Cardinal Tetra (Paracheirodon axelrodi)
Temperament
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Peaceful, schooling fish
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Should be kept in groups of 8–10+
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Larger groups increase comfort and showcase natural behavior
Adult Size
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1.5–2 inches
Minimum Tank Size
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20 gallons for a proper school
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Works beautifully in planted tanks and soft-water setups
Water Parameters
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Temperature: 74–82°F
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pH: 5.5–7.2
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Hardness: Soft water preferred (1–8 dGH)
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Ammonia/Nitrite: 0 ppm
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Nitrate: <20 ppm (sensitive to poor water quality)
Diet
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Omnivorous
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Accepts a wide variety of foods:
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High-quality micro-pellets or flake
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Frozen brine shrimp, daphnia, bloodworms
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Micro foods like cyclops
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Feed small portions 1–2× daily
Behavior & Compatibility
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Ideal community fish
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Compatible with:
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Corydoras
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Apistogrammas (peaceful dwarf cichlids)
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Rasboras
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Small gouramis
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Shrimp
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Other tetras
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Avoid:
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Large or predatory fish
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Fin-nippers
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Aquarium Setup
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Planted tanks strongly recommended
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Driftwood, leaf litter, or dim lighting enhance coloration
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Gentle filtration and clean water
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Dark substrate helps colors pop
Care Level
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Moderate
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Does best in stable, mature aquariums
Lifespan
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4–5 years with excellent care
Special Notes
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More sensitive than neon tetras but far more vibrant
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Thrive in low-stress environments with plenty of cover
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Wild-caught origins mean they prefer soft, warm, clean water
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Schooling behavior is most impressive in tanks with open midwater space
