Pristella is a small genus of South American tetras best known through Pristella maxillaris, the X-ray tetra, one of the most recognisable and widely kept characins in the aquarium hobby. The atlas's 2 species, 1–2 in as adults, come from the Amazon and Orinoco basins - the brief lists Brazil, Colombia, French Guiana, Guyana, Suriname, and Venezuela - and share a near-transparent body through which the skeleton and swim bladder are visible, along with a distinctive black-white-yellow patterned dorsal fin.
Pristella maxillaris has been a staple community aquarium fish for decades: peaceful, active in a school, tolerant of a wide range of water conditions, and unusually able among tetras to handle slightly brackish or mineral-rich water, which likely reflects the genus's presence in varied lowland habitats across its range. The second species, Pristella ariporo, is far less documented and has no meaningful presence in the trade. Both atlas species currently carry a Least Concern IUCN status.