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 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 friendly 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 will 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 prefer heavily planted aquariums that imitate a more natural habitat. A soft sandy substrate and some driftwood roots and branches are ideal. Adding dried leaf litter would further accentuate the natural feel and 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 tail's 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.


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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℃

Natural Habitat

Rio Negro


In the home aquarium, the Cardinal Tetra will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements.

Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide additional benefits to your fish's health and well-being but is not a must for this fish.

It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages.

This fish is an omnivore in the wild, meaning it will consume some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Tank Mates

10 interesting tank mate ideas for the Cardinal Tetra could 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 Gudgeon(Tateurndina Ocellicauda)
Pentazona Barb(Desmopuntius Pentazona)

Sexual Dimorphism

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 become slightly more prominent and plumper than males. In contrast, males will be much slimmer and have a hooked anal fin.

The Cardinal Tetra has been featured on the following stamps

Nicaragua - 1981
Cambodia - 1988

Frequently asked questions

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

Adonis Tetra(Lepidarchus adonis)
African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Arowana Tetra(Gnathocharax steindachneri)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
View all Tetras
Date Added: 08/05/2020 - Updated: 08/08/2022 18:06:36