Arguably the most popular of the small tetras, the cardinal tetra is similar in appearance to a longtime aquarium favorite, the neon tetra. Cardinal tetras are an active schooling fish, and they live peacefully in a community aquarium. Although they are difficult to breed in captivity, tetras remain a very popular aquarium fish. 
Species Overview
COMMON NAMES: Cardinal tetra, large neon tetra, red neon, roter neon
SCIENTIFIC NAME: Paracheirodon axelrodi
ADULT SIZE: 2 inches
LIFE EXPECTANCY: 4 years
Characteristics 
Family
Characidae
Origin
Brazil, Colombia, and Venezuela
Social
Peaceful, suitable for a community tank
Tank Level
Top to mid-dweller
Minimum Tank Size
20 gallon
Diet
Omnivore
Breeding
Egglayer
Care
Intermediate
pH
4.6 to 6.2
Hardness
Up to 4 dGH
Temperature
73 to 81 degrees F (23 to 27 degrees C)