Carinotetraodon is a genus of small freshwater pufferfish native to Southeast and South Asia, with atlas species recorded from Malaysia, India, Brunei, Cambodia, Indonesia, Thailand, and Vietnam. The genus name references the keel-like dorsal ridge that males of several species develop, most visible when displaying or breeding - a distinctive trait among freshwater puffers. Atlas species are tiny even by puffer standards, spanning roughly 1–2.5 in as adults, and like other tetraodontids they lack true scales, instead relying on a tough, spiny skin.
This is one of the aquarium hobby's most popular dwarf-puffer genera. The pea puffer, Carinotetraodon travancoricus, is a fixture of the nano and species-only tank scene worldwide, prized for its tiny size and personality despite a reputation for nipping tankmates; the redeye puffer (C. lorteti), striped redeye puffer (C. salivator), red-bellied dwarf puffer (C. irrubesco), and dwarf Malabar puffer (C. imitator) are also traded, generally by specialists willing to feed the live or frozen snails and other meaty foods these puffers need. The IUCN picture includes a Vulnerable and a Near Threatened species alongside mostly Least Concern and Data Deficient assessments, a reminder that popularity in the trade does not always track with security in the wild.