Paracheirodon is a genus of freshwater fish in the characin family (family Characidae) of order Characiformes. The type species is Paracheirodon innesi, the well-known neon tetra, and the Paracheirodon species are among the fishes known as tetras. All species of this genus are native to the Neotropic ecozone, occurring in the Orinoco and Amazon Basin in northern South America.
The Paracheirodon tetras reach maximum overall lengths of 2.5 to 5 cm (0.98 to 2.0 in) depending on the species involved, and are of elongated, tetra shape. All share a distinctive iridescent blue lateral line, but differ slightly in their other colorations.
Preferring soft, acidic waters, these midwater shoaling fishes feed predominantly on small crustaceans, insects, worms, and zooplankton. When spawning, they scatter their eggs and guard neither eggs nor young.
There are currently three recognized species in this genus:
- Paracheirodon axelrodi (L. P. Schultz, 1956) (cardinal tetra)
- Paracheirodon innesi (G. S. Myers, 1936) (neon tetra)
- Paracheirodon simulans (Géry, 1963) (green neon tetra)