Acrobrycon is a genus of characins from Andean piedmont streams of Bolivia, Peru, and Argentina, the transitional foothill drainages where fast Andean water slows into the lowland Amazon system. Atlas species range 2.5–4.5 in, on the larger side for tetras. As fish of swifter, cooler piedmont streams rather than warm Amazon lowland blackwater, they occupy a somewhat different niche within the characin family from the classic soft, tannin-stained-water tetras most aquarists know.
The sapphire tetra (A. ipanquianus) is the species with the most aquarium recognition, named for an iridescent blue sheen along the body, though it remains an uncommon, specialist import rather than a shop staple; A. ortii and A. starnesi are little known outside scientific collections. Conservation status leans favourable but not uniformly so: two of the three atlas species are Least Concern, while the third is Near Threatened, a sign of localized pressure somewhere within this Andean-piedmont range.