Cardinal Tetra
Paracheirodon axelrodi
Magnificent small South American tetra displaying an electric blue horizontal stripe along the entire body length and a bright red belly. Very popular in aquarium keeping, it requires soft and acidic water as well as group maintenance to thrive. Quintessential schooling fish, peaceful and active, ideal for planted Amazonian-type community aquariums.
Parameters
- Water type
- Freshwater
- Min volume
- 100 L
- Temperature
- 24–28 °C
- pH
- 4.5–6.5
- Hardness (GH)
- 1–6 °GH
- Adult size
- 5 cm
- Lifespan
- 5 years
- Diet
- omnivore
- Temperament
- paisible
- Difficulty
- intermédiaire
Environment
Minimum 100 liters for a group of 10-15 individuals minimum (ideally 20+). Planted aquarium with shaded areas, roots, branches and dark substrate to enhance its colors. Prefers subdued lighting (floating plants). Soft and acidic water imperative: pH 4.5-6.5, GH 1-6, temperature 24-28°C. Efficient filtration but moderate current. Use of peat or Catappa leaves recommended to recreate Amazonian blackwater conditions. Regular water changes (10% weekly) essential.
Feeding
Omnivore with insectivorous tendency. Readily accepts quality flakes and pellets, but requires regular supply of live or frozen food: bloodworms, daphnia, brine shrimp, microworms. Vary diet to maintain vibrant colors and health. Distribute in small quantities 2-3 times daily. Appreciates micro-organisms in a well-planted and mature aquarium.
Health & common diseases
The Cardinal Tetra is susceptible to white spot disease (Ichthyophthirius) and fin rot, especially under stress or poor water quality. It can also be affected by neon tetra disease (Pleistophora hyphessobryconis), an incurable parasitic infection that causes discoloration and erratic swimming. To prevent these problems, maintain clean and stable water (regular changes, constant temperature 24-26°C), avoid overcrowding, and quarantine new fish before introduction.
Tips & tankmates
Obligatory schooling fish: never keep fewer than 10 individuals or risk stress and abnormal behavior. Ideal cohabitation with Corydoras, small Loricariids, Apistogramma, other peaceful South American tetras. Avoid aggressive or oversized fish that would prey on them. Sensitive to water quality: avoid high nitrates, strictly respect soft water parameters. Beware of neon tetra disease (Pleistophora): quarantine recommended, no known treatment. Avoid abrupt introduction into an immature tank. Wild species often collected in the Amazon: favor captive-bred specimens when possible for ecological and adaptation reasons. Very active school during daytime, spectacular in an Amazonian biotope tank.
Sources
- Seriously Fish - Paracheirodon axelrodi
- Fishbase - Paracheirodon axelrodi
- Aquarium Atlas, Baensch & Riehl
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