American Characins - Cardinal Tetra (Paracheirodon axelrodi)

Aquarium Atlas Vol. I

Bilyap Aquaristic

Cardinal Tetra is one of the finest and most popular species. It is a small school fish which must be kept in groups of at least ten individuals. The more the better; a large school is not only more natural for this shoal fish but also a much more impressive sight in a home aquarium.

Cardinal Tetra's natural habitat is slow or standing waters of Amazon. It prefers clear water and dim-light areas shaded by terrestrial plants. Especially the fry has a kind of light phobia. The eggs are generally laid at night in total darkness. Cardinal Tetra inhabits rather shallow waters up to a depth of 40 cm and avoids fast currents.

Because breeding Cardinal Tetra is a relatively difficult task most specimens sold in pet shops are wild caught animals. The acclimatization of such wild caught fish might present some problems due to the weakened immune systems caused by the stress of transport. First weeks are very critical and substantial losses are common. But once successfully acclimatized Cardinal Tetra is not a difficult fish which may live five or more years in a home aquarium. Especially wild caught fish are prone to kidney disorders if kept in hard water. Soft and acidic water (GH < 4 d, pH < 7.0) is recommended for a long-run health.

Cardinal Tetra required very soft and acidic water for breeding. The breeding aquarium must be located in a shadowy place. Ideal water conditions: Conductivity as low as 15-20 micro siemens (GH almost zero), pH 5.5-6.2, temperature 26-28 C. Pure water from reverse-osmosis can be used for breeding after peat filtering. A young pair (7-8 months old) must be chosen for breeding. Up to 500 adhesive eggs are scattered around on fine leaved plants. Parents must be removed after spawning because they are notorious egg eaters. The eggs hatch in about 28 hours.

Raising the young requires patience because the fry of this species needs fine food for quite a long period of time (up to 8 weeks). Freshly hatched brine shrimp larvae must be supplemented with infusoria.