With almost 1,200 species, Characins rival the Cyprinidae family in numbers in the wild. This family contains many popular fish. Among the tetras, for example, are found the brilliant neons and cardinals, distant relatives to the notorious piranha, which brings us to one of the main characteristics of this family – teeth. They have extremely sharp teeth, even though not all characins are meat-eaters or predatory. Body size varies in the wild, from 1 in of the South American neon tetra to 12 in of the African long-nosed Distichodus. Shapes are equally diverse: Hatchetfish are flat-backed and deep-bodied, while Pencilfish are as slim as their name suggests. Piranhas are muscular, producing good speed, with teeth forward in the jaw to facilitate flesh tearing. Other Characins are not as carnivores but happily eat aquarium plants.
Many Characins are natural schoolers, but differences in mouth position affect feeding habits: Hatchetfish have upturned mouths, well suited to catching insects. Most of the popular tetras have mouths suited for midwater feeding.
Most characins spawn by means of egg scattering among plants. An exception is the splashing tetra, which lays its eggs out of the water to protect them from predators. Although the eggs remain safe, they must be kept moist – constant splashing is required by the male swimming below.
The Cardinal tetra (Paracheirodon axelrodi) is a very popular aquarium fish species that appreciates a shady aquarium with clear areas of water into which it can venture. Avoid excessive water currents and bright lighting. Although it can tolerate most water conditions satisfactorily, soft, acidic water encourages the best colors.
Black phantom tetra
The Black phantom tetra (Hyphessobrycon megalopterus) species likes a generously planted aquarium, with smaller, non-boisterous fishes. It needs soft, acidic water for its well being in general, and especially if breeding is to be attempted. Light sensitive eggs are usually scattered in plants. The body coloration is a transparent silvery gray. A black teardrop-shaped mark appears on the fish’s shoulder and is outlined by a surrounding bright area, and the fins are black.