The Characidae, characids or characins are a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their status as a by and large monophyletic group at family rank. To arrive there, this family has undergone much systematic and taxonomic change. Among those fishes that remain in the Characidae for the time being are the tetras, comprising the very similar genera Hemigrammus and Hyphessobrycon, as well as a few related forms such as the cave and neon tetras. Fish of this family are important as food and also include popular aquarium fish species.

These fish vary in length, though many are less than 3 centimetres (1 in). The smallest species^{[citation needed]} grows to a maximum length of 13 millimetres (0.5 in).

These fish inhabit a wide range and a variety of habitats. They originate in the Americas, ranging from southwestern Texas and Mexico through Central and South America. Many of these fish come from rivers, but for example the blind cave tetra even inhabits caves.