Species Spotlight: Cardinal Tetra (Paracheirodon Axelrodi)

Home > Library > Species Spotlight > Aquatic > Freshwater Aquarium > Freshwater Fish > Characidae Family > Cardinal Tetra (Paracheirodon Axelrodi)

Species Overview and Background:

Scientific Name: Paracheirodon Axelrodi
Common Names: Cardinal Tetra, Red Neon Tetra
Temperament: Peaceful
Care Level: Intermediate
Life Span: 2-4 years

The Cardinal Tetra (Paracheirodon Axelrodi) was first discovered in 1956 in the upper Orinoco and Negro rivers in South America, specifically in Brazil, Colombia, and Venezuela. It is native to the Amazon River basin.
In its natural habitat, Cardinal Tetras inhabit slow-moving waters such as streams, tributaries, and flooded areas of the rainforest. They are typically found in densely vegetated areas with dim lighting.
Cardinal Tetras are known to live together with others of the same species, forming large shoals that provide safety and social interaction.
In their natural environment, Cardinal Tetras actively feed on small insects, worms, crustaceans, and zooplankton.
The natural behaviour of Cardinal Tetras is peaceful. They are not aggressive or territorial. They prefer to live in large groups and feel more secure when surrounded by their own kind.
Cardinal Tetras were introduced in the aquarium hobby in the 1960s.
They have become famous due to their vibrant coloration and striking appearance, particularly their bright red and blue iridescent stripes.
Cardinal Tetras are relatively common in the aquarium hobby and are readily available in pet stores and from reputable breeders.
The ideal minimum group size for Cardinal Tetras in a tank is 10 individuals. A tank size of at least 60 litres (15 gallons) is recommended to accommodate their social nature and provide ample swimming space.
Cardinal Tetras are not a cross of other species. They are a distinct species within the tetra family. The first ones appeared naturally in the wild, and it is unclear who bred them first in captivity.

General Water Parameters:

pH Range: 5.0-7.0
Temperature Range: 23-28°C (73-82°F)
GH Range: 1-5 dGH
KH Range: 1-2 dKH
TDS Range: 50-100 ppm

Colour & Appearance:

Cardinal Tetras are small, slender fish with a maximum size of about 5 centimetres (2 inches) in length.
They have a sleek body shape and are characterized by their vibrant coloration. The upper half of their body is bright red, while the lower half is a deep blue iridescent stripe.
The colour intensity can vary among individuals, with some displaying more vivid colours than others.
In terms of variations, Cardinal Tetras are typically consistent in their coloration and pattern. However, due to selective breeding efforts, some variations with slightly different shades or intensities of red and blue may be available in the aquarium trade.

Care and Requirements:

Cardinal Tetras require a moderate level of care and are suitable for intermediate aquarists.
They are omnivorous and accept a variety of foods, including high-quality flake, pellet, and freeze-dried foods specifically formulated for small tropical fish.
Offering a varied diet that includes live or frozen foods such as brine shrimp, daphnia, and bloodworms will help ensure their nutritional needs are met.
Cardinal Tetras are relatively hardy, but they are sensitive to poor water quality. Regular water changes and proper filtration are essential to maintain good water parameters.
They are active during the day and spend their time swimming in the mid to upper levels of the aquarium.

While they may occasionally seek refuge in plants or decorative structures, Cardinal Tetras generally prefer swimming in open spaces and appreciate a well-lit aquarium.

Diet:

Cardinal Tetras are primarily omnivorous and have a versatile diet.
In the wild, they feed on small insects, worms, crustaceans, and zooplankton.
In captivity, they readily accept high-quality flake and pellet foods designed for small tropical fish.
It is recommended to supplement their diet with live or frozen foods such as brine shrimp, daphnia, and bloodworms to provide additional variety and nutrition.
Cardinal Tetras may also feed on microorganisms and biofilm present in the tank, contributing to the overall ecosystem balance.
It is important to provide a balanced diet and avoid overfeeding to prevent water quality issues.

Ideal Tank Setup:

Cardinal Tetras thrive in well-maintained aquariums with suitable water parameters and appropriate tank setups.
A tank size of at least 60 litres (15 gallons) is recommended to accommodate a school of Cardinal Tetras.
They prefer a planted aquarium with dense vegetation, which provides them with security and mimics their natural habitat.
Floating plants such as Amazon frogbit or water lettuce can help diffuse the lighting and create shaded areas.
For substrate, a fine gravel or sandy substrate is suitable. Avoid using sharp or coarse substrates that may damage their delicate fins.
Adding driftwood and rocks can create natural hiding places and serve as decorative elements in the tank.
Cardinal Tetras appreciate a moderate water flow in the tank, mimicking the gentle currents of their natural habitat. This can be achieved with the use of a low-powered filter or by positioning the filter outlet to create gentle circulation.
It is recommended to maintain a stable and clean environment by performing regular water changes and monitoring water parameters.

Compatible Tankmates:

Cardinal Tetras are peaceful and can coexist with a variety of other small, non-aggressive fish.
Suitable tankmates include other peaceful community fish such as small tetras (e.g., Neon Tetras, Rummy Nose Tetras), Corydoras catfish, small rasboras, and peaceful dwarf cichlids.
Avoid keeping them with larger, aggressive fish or fin-nipping species that may harm or stress them.
When selecting tankmates, consider their similar water parameter requirements to ensure compatibility and overall well-being of the fish community.

Sexing:

Distinguishing between male and female Cardinal Tetras can be challenging as there are no distinct external differences.
However, during the spawning period, females may appear slightly rounder and have a deeper body compared to males.
In some cases, the red coloration on the lower half of the body may be more intense in males.

Breeding:

It is possible to breed Cardinal Tetras in a hobbyist's aquarium, although it can be more challenging compared to other tetra species.
Creating the ideal breeding conditions is crucial. This can be achieved by providing soft and slightly acidic water with a pH of around 6.0-6.5.
Conditioning the breeding pair with high-quality live and frozen foods can help stimulate breeding behaviour.
A separate breeding tank with fine-leaved plants such as Java moss or spawning mops can be set up to serve as a spawning site.
The water level in the breeding tank should be shallow, around 10-15 centimetres (4-6 inches), and gentle filtration or a sponge filter can be used to maintain water quality.
Introducing the conditioned pair into the breeding tank and providing a dimly lit environment can trigger spawning.
After spawning, the adults should be removed from the tank to prevent them from eating the eggs.

The eggs typically hatch within 24-36 hours, and the fry can be fed with infusoria, or commercially available liquid fry food designed for small fish.

As the fry grow, they can be transitioned to baby brine shrimp and finely crushed flakes or pellets.
It is important to provide proper care and maintain water quality during the breeding process to ensure the successful development of the fry.

Additional Considerations:

When introducing Cardinal Tetras to a new aquarium, it is important to acclimate them slowly to prevent stress or shock.
Proper acclimation can be done by floating the sealed bag containing the fish in the aquarium for about 15-20 minutes to allow the temperature to equalize.
Gradually add small amounts of aquarium water to the bag over a period of time to allow the fish to adjust to the water chemistry.
After acclimation, gently release the fish into the tank.
Monitoring water parameters regularly, performing regular maintenance, and providing a well-balanced diet are essential for the long-term health and well-being of Cardinal Tetras.
Keep in mind that while Cardinal Tetras are generally hardy, sudden changes in water parameters or poor water quality can lead to stress and illness.
It is recommended to research and understand the specific needs of any fish species before adding them to your aquarium, ensuring you can provide a suitable environment and care for their requirements.

In conclusion, the Cardinal Tetra is a stunning and peaceful fish that can bring vibrant coloration and lively activity to a well-maintained aquarium. With proper care, suitable tank setup, and a balanced diet, they can thrive and provide a captivating display. Whether you are a beginner or an experienced aquarist, the Cardinal Tetra can be a rewarding addition to your aquatic community.