Cardinal tetra

Environment

Minimum 100 litres for a group of at least 10-15 individuals (ideally 20+). A planted aquarium with shaded areas, roots, branches and a dark substrate to highlight its colours. It prefers subdued lighting (floating plants). Soft, acidic water is essential: pH 4.5-6.5, GH 1-6, temperature 24-28°C. Effective filtration but moderate current. The use of peat or Catappa leaves is recommended to recreate Amazonian blackwater. Regular water changes (10% weekly) are essential.

Feeding

An omnivore with an insectivorous tendency. It readily accepts quality flakes and pellets, but needs regular live or frozen food: bloodworms, daphnia, brine shrimp, microworms. Vary the diet to maintain vivid colours and health. Feed in small amounts 2-3 times a day. It appreciates the micro-organisms in a well-planted, mature aquarium.

Tips & tankmates

An obligate schooling fish: never keep fewer than 10 individuals, or it will suffer stress and abnormal behaviour. Ideal cohabitation with Corydoras, small Loricariids, Apistogramma and other peaceful South American tetras. Avoid aggressive or overly large fish that would take them for prey. Sensitive to water quality: avoid high nitrates and strictly respect the soft-water parameters. Beware of neon disease (Pleistophora): quarantine recommended, no known treatment. Avoid abrupt introduction into an immature tank. Often a wild-caught species from the Amazon: favour captive-bred specimens where possible, for ecological and adaptation reasons. A very active school during the day, spectacular in an Amazonian biotope tank.

Sources

• Seriously Fish - Paracheirodon axelrodi
• Fishbase - Paracheirodon axelrodi
• Aquarium Atlas, Baensch & Riehl