Megalamphodinae

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.

Axelrodia is a genus of freshwater ray-finned fishes belonging to the family Acestrorhamphidae, the American tetras. The fishes in this genus are found in the Amazon Basin and Meta River in South America.

Brittanichthys is a genus of freshwater ray-finned fishes belonging to the family Acestrorhamphidae, the American tetras. The fishes in this genus are endemic to the Rio Negro basin in South America.

Petitella is a genus of freshwater ray-finned fishes belonging to the family Acestrorhamphidae, the American characins, of the order Characiformes. The fishes in this genus are found in South America.