Cardinal Tetra

Species Profile

• Scientific Name: Paracheirodon axelrodi
• Common Name: Cardinal Tetra
• Adult Size: 2 inches (5 cm)
• Life Expectancy: 4 to 5 years (can live longer with excellent care)
• Habitat: Native to the Orinoco and Negro River basins in South America (Brazil, Colombia, Venezuela). Found in shaded, slow-moving blackwater rivers rich in leaf litter and tannins.

Tank Requirements

• Minimum Tank Size: 15–20 gallons (best kept in a school of 8 or more)
• Ideal Temperature: 73–81°F (23–27°C)
• pH Range: 4.5–6.5 (acidic preferred)
• Water Hardness: 1–6 dGH (soft water)
• Temperament: Peaceful and schooling Best kept in groups of 8+
  Excellent for community aquariums with other non-aggressive fish

Diet & Nutrition

Omnivorous – Accepts:

• High-quality micro pellets and flakes
• Live or frozen foods: brine shrimp, daphnia, bloodworms

• Occasional vegetable-based foods

Feed small amounts once or twice a day.

Breeding & Spawning

• Breeding Difficulty: Moderate to difficult
• Requires very soft, acidic water, and dim lighting
• Spawning type: Egg scatterers
• Hatch Time: Eggs hatch in ~24–36 hours
• Adults should be removed after spawning to prevent egg predation

• Fry need very fine food (infusoria, then baby brine shrimp)

Appearance

• Body Shape: Slim, elongated body

• Coloration:

  • Brilliant neon blue stripe across entire length

  • Vibrant red stripe running from mid-body to tail (longer than in Neon Tetras)

Distinctive Features

• More intense red coloration compared to Neon Tetras
• Sensitive to sudden water changes; prefer blackwater or tannin-rich environments
• Perfect for planted tanks with low lighting
• Schooling behavior adds beauty and movement to the tank

• Considered one of the most visually striking tetra species