Characins

Characins are freshwater fishes belonging to the order Characiformes. In aquarium literature and common usage, the term refers to a broad group that includes tetras, pencilfishes, hatchetfishes, and related species. These fishes are distributed mainly in tropical regions of Africa and the Americas and comprise a wide range of sizes and shapes.

Most characins are small to medium-sized, with many adapted to riverine and floodplain habitats. They tend to be schooling, omnivorous or insectivorous, and prefer waters that are well-oxygenated and moderately soft. A characteristic feature for many species is the presence of an adipose fin behind the dorsal fin, though not all characins possess this fin.

Reproduction is typically egg-laying, with spawning among vegetation or substrate; there is considerable variation among species and some exhibit parental care in particular lineages.

In the home aquarium, characins such as neon tetras, cardinal tetras, and various hatchetfishes are popular; they require stable water conditions, moderate temperatures (roughly 22–26 C), and a varied diet. Their care and husbandry are best tailored to species-specific needs.

Taxonomy and conservation: The Characiformes group is taxonomically diverse and has undergone revisions; many genera once placed in Characidae have been moved to other families within Characiformes. Some characins are threatened by habitat destruction, pollution, and collection for the aquarium trade.