Cardinal Tetra - They may be small, but what outstanding color for a Tropical Freshwater Aquarium Fish!

text copyright by Ronald J. Noreen, photograph above top, from www.webshots.com, photograph above bottom, from www.wikipedia.com
Discovered and described by Indian researcher and aquarist Harald Schultz in 1956 and named for Herbert R. Axelrod, (Paracheirodon axelrodi) , these beautiful small tetras have always been one of my favorites. Their red,white and blue colors rival many saltwater fish. Although similar to the Neon Tetra, Paracheirodon innesi, the major difference is the red stripe which goes the full length of the fish on the Cardinal Tetra, but only halfway along the body of the Neon Tetra. Although it depends on the spectrum of the overhead lighting, the iridescent colors of the Cardinal Tetra tend to be a darker red and a deeper blue.
Neon Tetra
They are some of the first Tropical Fish that I kept back in the early 1970's. Truly stunning in a group of 15 or more, the smallest group should be no less than 6 for this shoaling / schooling species. Please use nothing smaller than a 20 gallon aquarium to allow for a school, several catfish and some algae eating scavengers.
Water chemistry that I found successful was a pH of 6.8 - 7.0 and a temperature of 78 - 80 degrees. I generally changed twenty five percent of the water every two weeks utilizing a standard water conditioner to remove chlorine. Your water conditions may warrant a chloramine remover, please check with your local water authority and the local fish store.
In recent years they have finally been bred and raised in quantity, in captivity, but they do not reproduce as readily as the Neon Tetra. Sometimes a bit difficult to keep initially, once settled in they are exceptional. I once kept a school of eight Cardinals that lived between six and eight years in a 40 gallon planted aquarium with other small tetras, loaches, dwarf cichlids, and catfish. Hiding in the plants in the photo above is another one of my favorites (I have too many!!), the Ram Cichlid, (Microgeophagus ramirizi). Cardinals will attain a size of approximately one and a half inches in length. There are now Golden Cardinals available too.
Try some 'retro' fishkeeping with a large school of these interesting fish, it will be well worth the effort involved.