Cardinal Tetra

Cardinal Tetra

Scientific classification

Kingdom: Animalia
Phylum:          Chordata
Class:               Actinopterygii
Order:              Characiforme
Family:            Characidae
Genus:              Paracheirodon
Species:           P. Axelrodi
Binomial name: Paracheirodon axelrodi

The Cardinal Tetra is scientifically named Paracheirodon Axelrod., This belongs to the Characin Group (Characidae family); is a freshwater fish. It is of the Characiformes Order, indigenous to the Negro Rivers of South America and the higher Orinoco. Its full-grown length is 3cm (1,25in.), The cardinal tetra possesses the uniqueness of the Paracheirodon varieties, that of having different colors glittering like a rainbow, literally dividing the fish in such a way, that the color of the body below the division is colored bright red. This gives it its name “cardinal tetra”. The characteristics of the cardinal tetra have a close resemblance to the Neon Tetra, with which it is always mistaken. The red color of the neon divides it lengthwise just about halfway up to the nose. Besides the blue stripes of the Neon Tetra is not that bright.

Cardinal Tetra

Habitat and Range

In the year 1956 Schultz gave a description of the Cardinal Tetra, scientifically named Paracheirodon Axelrodi. There is no record of this fish in the IUCN Red List. You can  find them in the woody regions, in the slow flowing Blackwater tributaries in the continent of South America, specifically the Rio Negro (this is the biggest of the world’s Blackwater Rivers) and one of the longest rivers of South America called Orinoco which measures 2140 Km.. Besides, the Cardinal Tetra is also found in Brazil and Venezuela. The canopy of the rainforest which is normally dense hinders light entering the waterways. The Cardinal Tetra dwells in shoals, particularly in the layers of the middle waters, and consumes tiny crustaceans and worms.

The majority of them displayed for sales are those that are trapped in the wild for trading for aquarium purposes, and reconstructing their captivity facilitating their environment that simulates their lifestyle in nature. Specimens bred in captivity are also available and of late, a “gold” strain of the Cardinal Tetra was produced which is seen occasionally.

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Of the tetra varieties the Cardinal Tetra is small, attaining a size of almost 2” (5 cm).  It survives up to 2 to 5 years in captivity. The coloration of their body is bluish, having a stripe stretching vertically from its nose all through the body length of electric blue neon color. There is a beautiful demarcation of a broad red colored stripe beneath the blue extending from the head to the back.  This resembles the Neon Tetra, except that the red stripes on the Neon Tetra stretches just half the length of its body.


People have succeeded in breeding the Cardinal Tetra in Aquariums, however, it is cumbersome breeding them and most of the Cardinal Tetras available in the pet stores are those caught in the wild from the Rio Negro and Rio Orinoco. While in nature, they are very productive and they do not fear of attacks in their habitat.  The Neon Tetra is a highly productive variety in captivity as well as in the wild unlike the Cardinal Tetra.  The lifespan of the Cardinal Tetra in the wild does not exceed a year, as a result of which they spawn in the young age.  However, in captivity, the lifespan of the Cardinal Tetra extends for many years.

The Cardinal Tetra scatters its eggs in the substratum/water without any protection.  It chooses laying its eggs between plants.  In a single spawn it brings out more than 500 eggs, that hatch after a period of 24 to 30 hours, further it needs 3 to 4 days before the babies gaining freedom can swim. These very tiny Cardinal Tetra fry find difficulty in consuming large food; hence give them minced fry food.

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How to Grow at Home


The fully developed Cardinal Tetra has a growth length of 3 to 5 cm (1.25 to 2 in) for which a big aquarium is not needed.  An aquarium of a capacity of 5 gallons is quite sufficient to house  a Cardinal Tetra.  This Cardinal Tetra is a peace loving variety, as such; you can see them in aquariums kept at home. It dwells in the middle as well as the top and takes in all types of food, even flake food.

The hardness and pH value of the water is not of concern for the Cardinal Tetra which has a high sensitivity for soluble waste, particularly nitrate. It is imperative that you change your water frequently. It is believed by certain people that the Cardinal Tetra is not the right one for the new hobbyist. However, if a fresher is prepared to often replace the water in the aquarium and spend some time entertaining his  fish, it is well and good.

Water Condition

The chemicals present in the Blackwater from where the Cardinal Tetra originates has an acidic pH having humic acids with low amounts of minerals. This variety adjusts to several conditions in custody, but changes in the chemistry of the soft and acidic water can cause a severe blow to its lifespan, spawning as well as productiveness.  The favored range of temperature is between 26°C to 28°C (78.8°F to 82.4°F). But according to the circumstances they survive in 24°C (75.2°F).  Ensure that the chemical composition of the water in your aquarium is similar to that of its original habitat. One method of obtaining this chemistry of water is by filtering the water of your aquarium above peat, and another way is to ensure that the water undergoes osmosis reversely.

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According to the studies in Manaus in Brazil, when Cardinal Tetra was subjected to  unfavorable weather conditions for four days. The fish died on account of temperature that was below 19.6°C or higher than 33.7 C, and when the value of pH was under 2.9 or exceeded 8.8.


The Cardinal Tetra accepts several tiny kinds of food, like Daphne or Brine Shrimp, Tubifex or Frozen and Dried Blood Worms, and a good variety of flake food, frozen and live dried food stuff. For excellent follow-up, occasionally, change its diet

Glow Light Tetra Setup:

Cardinal tetras are generally kept in clusters, with a minimum of 5 tetras. You would do well to keep a  bigger shoal, which means if the space in the tank is sufficient for 10 cardinal tetras or more, and you have less number of them, the fish becomes stressed and timid. Cardinal tetras are not violent;, they are normally seen in aquariums kept at homes along with other  peace loving varieties of tropical fishes of the same size. In case your choice is a fish that occupies the middle and upper part of the aquarium, well then the Cardinal tetra is the right choice.

60 cm (24 in.) is the suggested size of a small aquarium for your Cardinal tetra. When compared to the Neon, the Cardinal tetras are more susceptible to unhealthy water, besides having larger aquarium makes maintenance easier when compared to a small one because the quality of the water remains stable and good.  For a beginner it is important that the aquarium is bigger. A skilled hobbyist who has full knowledge of maintaining the quality of water can keep keep his/her Cardinal Tetras in a smaller aquarium that is less than 20 liters (5 gallons).

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