The Orinoco phenotype may represent a subspecies of P. The normal form from the Rio Negro drainage has a blue stripe, which extends to the adipose fin, while the Orinoco drainage phenotype has a stripe that stops posterior to the adipose. A 'gold' and 'silver-blonde' form exists in the Rio Negro drainage that has less blue in the longitudinal stripe. The species exists in a number of different color forms or phenotypes. axelrodi is also often called the red neon tetra. The fish's common name, cardinal tetra, refers to the brilliant red coloration, reminiscent of a cardinal's robes. Hyphessobrycon cardinalis is an obsolete synonym. The specific epithet honors ichthyologist Herbert R. Īmerican ichthyologist Leonard Peter Schultz described the cardinal tetra in 1956 as Cheirodon axelrodi. If those fishermen lost their livelihoods catching cardinals and other tropical fish, they might turn their attention to engaging in deforestation.

Some ichthyologists believe fishkeepers should continue to support the sustainable cardinal fishery of the Amazon Basin, since thousands of people are employed in the region to capture fish for the aquarium trade. However, many breeders are now producing the fish in most cases, one can determine if the cardinal tetra is bred or wild-caught due to damaged fins on wild-caught specimens. The cardinal tetra is a very popular aquarium fish, but is less widespread than the neon tetra because until recently, it was difficult to breed in captivity. The cardinal tetra's appearance is similar to that of the closely related neon tetra, with which it is often confused the neon's red coloration extends only about halfway to the nose, and the neon's blue stripe is a less vibrant blue. Growing to about 3 cm (1.2 in) total length, the cardinal tetra has the striking iridescent blue line characteristic of the genus Paracheirodon laterally bisecting the fish, with the body below this line being vivid red in color, hence the name ' cardinal tetra'. It is native to the upper Orinoco and Negro Rivers in South America. The cardinal tetra ( Paracheirodon axelrodi) is a freshwater fish of the family Characidae of order Characiformes. Hyphessobrycon cardinalis Myers & Weitzman, 1956.

Cardinal tetra