Max Size: 5cm

Cardinal Tetra (Paracheirodon axelrodi)

The Cardinal Tetra (Paracheirodon axelrodi) is seemingly one of the most popular fish species for the aquarium. It is often confused with the Neon tetra as it is somewhat similar in appearance.

Cardinal Tetras are perfect for beginner aquarists as they are relatively hardy, easy to care for and very colourful. Like most Tetras, Cardinal Tetras are peaceful and make an excellent addition to any community aquarium; however, you can also keep these fish in a species only aquarium.

The Cardinal Tetra is a very sociable fish that you should keep in larger groups of at least eight, preferably more; this way, they can create tight groups and create a dazzling shoaling effect that forms the focal point of any aquarium. In addition, these fish are also much more confident when around others of their kind. But, on the other hand, these Tetras can become shy and stressed and even lose their colour if kept alone.

Ideal tankmates for Cardinal Tetras can include other Tetras, Hatchetfish, Pencilfish, Corydoras Catfish and non-aggressive, small to medium-sized Cichlids. However, it would be better to avoid much larger or more aggressive fish as they will easily intimidate them as they cannot defend themselves.

They are more susceptible to poor water quality than their Neon cousins, and they prefer heavily planted aquariums that imitate a more natural habitat. Soft sandy substrate and some driftwood roots and branches are ideal. Adding dried leaf litter would further accentuate the natural feel and will also offer additional cover for your fish.

Cardinal Tetras bodies are typically slender and torpedo-shaped with blue and red colouring. These Tetras have an iridescent blue stripe that runs from the tip of the nose and stops at the tails base. Directly below the blue bar is a wider bright red band. The red band runs down the entire length of the body and through the transparent tail. All of the fins on this Tetra are transparent, and their belly is usually white. You can also find Cardinal Tetras in golds and silvers; however, these are far less common.

Tank Mates for the Cardinal Tetra

10 ideal tank mate ideas for the Cardinal Tetra include:

Adolfos Catfish(Corydoras adolfoi)
Black Neon Tetra(Hyphessobrycon herbertaxelrodi)
Blue Purple Emperor Tetra(Inpaichthys kerri)
Cherry Barb(Puntius titteya)
Dwarf Pencilfish(Nannostomus marginatus)
Hovering Zebra Loach(Yunnanilus cruciatus, Micronemacheilus cruciatus, Nemacheilus cruciatus)
Kuhli Loach(Pangio kuhlii)
Neon Tetra(Paracheirodon innesi)
Peacock Goby(Tateurndina Ocellicauda)
Pentazona Barb(Desmopuntius Pentazona)
Quick Facts
Scientific NameParacheirodon axelrodi
Year Described1956
Other NamesRed Neon, Roter Neon
OriginsBrazil, Colombia, Venezuela
Aquarium LevelMiddle - Top
Best kept asGroups 6+
Lifespan4 - 5 years
Water Parameters
Water TypeFreshwater
PH3.5 - 7.5
GH1 - 5
KH2 - 6
TDS20 - 215
73 - 84℉
23 - 29℃

Photos of the Cardinal Tetra

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Cardinal Tetra School
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Cardinal Tetra
Cardinal Tetra School
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Natural Habitat

Cardinal Tetras are endemic to the upper Orinoco and the Rio Negro river basins located in Columbia, Venezuela and Brazil in South America. They inhabit slow-moving waters in creeks, rivers, canals and streams. Their habitats usually comprise thick, overhanging, riparian vegetation, and the substrate is generally made up of fallen branches, tree roots and leaf litter. Also, these Tetras prefer shaded areas with low or subdued lighting.

Rio Negro

What to feed the Cardinal Tetra

Cardinal Tetras are unfussy and will accept most food offered in the aquarium. However, it would be best to provide them with a balanced diet comprising high-quality dried foods such as flakes, granules and pellets alongside frozen and live food such as brine shrimp, daphnia, bloodworms and Tubifex.

It would also be beneficial to your Tetras if you added some green vegetables to their diet as this will keep your Tetras healthy and will also help your fish maintain their colour.

How to sex the Cardinal Tetra

The male and female Cardinal Tetras are similar in appearance and colour, making it quite challenging to determine their gender when young. However, as the fish mature, this becomes easier to define as the females will become slightly larger and plumper than males. In contrast, males will be much slimmer and will have a hooked anal fin.

How to breed the Cardinal Tetra

When it comes to breeding the Cardinal Tetra, it is advisable to provide them with a separate dimly lit breeding tank comprising very soft water and plenty of plants and moss. It would also help if you conditioned the fish with live and frozen foods, encouraging spawning behaviour.

When the couple is ready to spawn, the female's stomach will become full of eggs. It is at this point you should place them in the breeding tank. Next, the female will allow a male to swim beside her as they move around plants. The fish will then release eggs and sperm.

If breeding has been successful, the pair will typically spawn during the evening, where the female will scatter a few hundred eggs. Once the eggs have been released, you should remove the parents as quickly as possible; otherwise, the adults may consume them. The eggs will usually hatch around three days later.

Initially, the fry will be too small to eat the same as the adults, so it is best to feed them small foods like infusoria until they are big enough to accept more significant foods.

Once hatched, the young will be sensitive to light, so it would be better if you gradually raised the light intensity back to normal conditions. Then, around 8 to 12 weeks later, the fry should start displaying the same colours as the adults.

The Cardinal Tetra has been featured on the following stamps

Nicaragua - 1981
Cambodia - 1988

Frquently asked questions about the Cardinal Tetra

Can Cardinal Tetras live with Neon Tetras?

Yes, Cardinal Tetras are very similar to Neon Tetras in their care and appearance and will frequently school together in the home aquarium.

How do you tell the difference between a Cardinal Tetra and a Neon Tetra?

The main difference between a Cardinal Tetra and a Neon Tetra is the length of their stripe. Cardinals stripe runs through the entire length of the body whereas the Neons stripe only runs through half of the body.

Other Tetras of interest

African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
Black Neon Tetra(Hyphessobrycon herbertaxelrodi)
Black Phantom Tetra(Hyphessobrycon megalopterus)
View all Tetras
Date Added: 08/05/2020 - Updated: 15/02/2022 17:14:41