Cardinals are native to the Amazon basin in South America and occur in two distinct populations. Firstly, the most prolific location is around Manaus in central Brazil, primarily in the Rio Negro and its tributaries. The second distinct population is in Columbia in the Rio Meta and its tributaries. Most supplies to our trade are from wild-caught fish and as such the supply is regulated by flooding and other natural phenomena. Cardinal tetras are a peaceful fish preferring soft & slightly acid water.
Tetras are considered easy to keep in a community aquarium of at least 20L, with a pH of 5.07.0 and KH of 1.02.0. However, they will not tolerate dramatic changes to their environment. The Tetra can live 10 years or more with the proper conditions. They tend to be timid and, because of their small size, should not be kept with large or aggressive fish who may bully or simply eat them.
Fish that mix well in an aquarium are other types of tetras, and other community fish that live well in an ideal Tetra water condition. Mid-level feeders, they are best kept in schools of five to eight or more, for the "shoaling" effect when they move around the tank. They shoal naturally in the wild and are thus happier, more brightly coloured, and more active when kept as a shoal as opposed to singly.
Tetras are best kept in a densely planted tank with subdued light and an ideal temperature of 2024?C to resemble their native Amazon environment. Tetras are omnivores and will accept most flake foods, but should also have some small foods such as brine shrimp, daphnia, freeze-dried bloodworms, tubifex, and micro pellet food to supplement their diet.