Cardinal tetra - Paracheirodon axelrodi

Scientific name: Paracheirodon axelrodi

Common name: Cardinal tetra

Family: Characidae

Usual size in fish tanks: 4 - 5 cm (1.57 - 1.97 inch)

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Recommended pH range for the species: 4.5 - 7

Recommended water hardness (dGH): 0 - 8°N (0 - 142.86ppm)

0°C 32°F30°C 86°F

Recommended temperature: 23 - 29 °C (73.4 - 84.2°F)

The way how these fish reproduce: Spawning

Where the species comes from: South America

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Middle levels

Food

The Cardinal Tetra (Paracheirodon axelrodi) is an omnivore that thrives on a varied diet. They will readily accept high-quality flakes, algae-based foods, and small live or frozen treats like brine shrimp and microworms. Providing a balanced diet that includes both plant-based and protein-rich foods helps maintain their bright coloration and overall health.

Sexing

Sexually mature females are slightly larger and plumper than males, especially when carrying eggs. Males, in contrast, tend to have a more slender body and slightly straighter ventral lines.

Breeding

Breeding Cardinal Tetras requires careful attention to their environmental needs. These fish prefer to spawn in very dark, shaded areas, as their eggs are highly sensitive to light. The male and female will swim side by side, releasing eggs and sperm simultaneously. The eggs hatch within 2-3 days, and the fry should be kept in complete darkness for at least another 7 days to avoid light-induced damage. Soft, acidic water with a pH of 5-6 and a temperature of 25-27°C (77-80.6°F) is ideal for successful breeding.

Lifespan

In the wild, Cardinal Tetras typically live for just one year due to environmental pressures. However, in captivity, they can live up to 3 years with proper care, including a stable environment, high water quality, and a balanced diet.

Origin

The Cardinal Tetra originates from South America, specifically the Orinoco River Basin in Venezuela and Colombia, and the Rio Negro Basin in Brazil. These waters are soft, acidic, and often densely vegetated, providing the shaded conditions these tetras favor.

Description

The Cardinal Tetra (Paracheirodon axelrodi) is renowned for its striking appearance, which resembles the vivid red and blue coloration of the cardinal bird. Often referred to as the "Red Neon Tetra," this fish is distinguished by its bright red stripe running from its mid-body to the tail and a neon blue stripe that extends from its nose to its dorsal fin. Its small size, peaceful nature, and vibrant colors make it a popular choice among aquarists.

Suitable Plants

To mimic their natural habitat, consider adding plants that thrive in soft, acidic water. Ideal choices include:

Amazon Sword - Provides excellent cover and visual barriers.
Java Moss - Offers shade and serves as a hiding spot for fry.
Floating Plants like Duckweed or Frogbit - Reduce light intensity and create a more shaded environment.
Anubias - Hardy and adaptable, perfect for soft water setups.

Compatible Fish Species

The peaceful nature of Cardinal Tetras makes them excellent tankmates for other non-aggressive species. Suitable companions include:

Neon Tetras - Share similar water requirements and behaviors.
Ember Tetras - Small and equally peaceful, adding vibrant orange hues to the tank.
Corydoras Catfish - Bottom dwellers that won’t compete for swimming space.
Otocinclus Catfish - Algae eaters that thrive in similar conditions.
Honey Gouramis - Gentle fish that add a unique dynamic to the tank.

Avoid keeping Cardinal Tetras with larger, aggressive fish such as cichlids, which may see them as prey.