Paracheirodon

Paracheirodon is a genus of freshwater ray-finned fishes belonging to the family Acestrorhamphidae, the American characins, of the order Characiformes. The type species is P. 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 Neotropical realm, occurring in the Orinoco and Amazon Basins in northern South America.

Paracheirodon tetras reach maximum overall lengths of 2.5 to 5 cm (0.98 to 1.97 in) depending on the species, and are of elongated, tetra shapes. All share a distinctive iridescent blue lateral line, but differ slightly in their other colorations.