In 2013, a wave of molecular research reshaped the pufferfish family tree. Genera once grouped under Tetraodon were split into Pao, Dichotomyctere, and Leiodon, revealing deep evolutionary divides hidden by outward similarity. This landmark reclassification transformed both science and the aquarium hobby, marking the moment when modern genetics redefined how we understand pufferfish lineage and identity.

Sphoeroides asellus (syn. Colomesus asellus), commonly sold as the Amazon puffer (also Peruvian or South American puffer), is a small New-World puffer endemic to major northern South American drainages (Amazon mainstem and tributaries; also reported from the Orinoco/near-coastal reaches), occurring primarily in fresh water with some tolerance of estuarine conditions.