The Costello tetra is a species of characin from the Amazon basin and is found in Brazil and Peru.

[1] The specific name comes from Lake Hyanuary in Brazil.

[2] Other common names used in English are January tetra and green neon.

The name "green neon" is also used for Paracheirodon simulans.

Wild caught specimens sport a characteristic golden sheen to their scales, this is due to the presence of a parasite found within their native range that causes the unusual pigmentation, captive bred Costello tetra do not display this coloration, and instead present with a silver iridescent scalation, more typical of many others within the Characidae family.