Most Characins are schooling fish so they do better in a community aquarium with lots of buddies to hang out with. Apart from the predatory species such as the Piranhas, most Characins are peaceful even though many are carnivores. In the aquarium tetras usually prefer clear, slightly acidic water with strong currents and highly oxygenated water provided by a strong filter and good surface movement. Most will eat a tropical flake food which contains both proteins and vegetable. You can supplement this with additional proteins such as black worms, bloodworms, or even brine shrimp for those that are carnivorous.