The cardinal tetra (Paracheirodon axelrodi) is a freshwater fish which is in great demand in aquarium trade nowadays. Its striking resemblance to the neon tetra (Paracheirodon innesi) leads to a great deal of confusion between the two. While the characteristic bright red coloration is restricted to the rear half in the neon tetra species, in the cardinal species, the same spans the lower half of the body. Cardinal Tetra Fish Care The cardinal tetra is less popular than the neon tetra as it is very difficult to breed this species in captivity. Also, the species has a lifespan of about 1 year, especially in their natural habitat. In captivity, it will live on for several years. Given below are some pointers that will help you take proper care of your pet tetra. At 3 to 5 centimeters in length, the cardinal tetra is a tiny fish, and therefore, a fish tank that is roughly about 5 gallons should suffice. The tetra family has top-dwelling as well as mid-dwelling species to its credit, which can live peacefully in community tanks. The temperature of the water should be between 73ºC to 81ºC, or a little higher, and the pH level should be between 4.6 to 6.2. The species can adapt to hard water and even alkaline water pH, but that makes them more sensitive to change. You can provide some plants along the border of the aquarium, but keep in mind that the species needs a lot of open space to swim in the center of the tank. You should not bring home a lone cardinal tetra as these fish love swimming in schools. An ideal number would be around 8-10 fish. The tetra species is omnivorous in nature, and will eat most of the types of food, including flake food. You can feed your tetra with freeze-dried bloodworms, tubifex, brine shrimp, daphnia, etc. As for the fry, i.e., the young fish, they should only be given tiny bits of food as they themselves are miniature in size; newly hatched brine shrimp would be an apt choice. If you are thinking of breeding this species, then you will have to put in a lot of efforts. It is difficult to breed them in captivity, and even if the fish do spawn, the death rates are considerably high among fry. A female will lay about 500 eggs in a single spawning. Once the eggs are laid, it will be a better idea to separate the adults from the eggs, or else they will end up feeding on their own eggs. One of the most prominent diseases that affect the cardinal tetra is the white spot disease, the Ich, which is caused by Ichthyophthirius multifiliis, a common parasite affecting aquarium fish. The species is also prone to several intestinal parasite diseases. In favorable conditions though, they becomes resistant to several diseases. Considering their size and temperament, it is but obvious that you should keep them with similar sized, docile fish, or they will end up being eaten by large species. The cardinal tetra may cost more than the neon tetra, which can be attributed to the fact that it is difficult to breed the species in captivity. Usually they are captured from their natural habitat, i.e., the upper Orinoco and Negro basins in South America.