Rhoadsia is a genus of characins from the Pacific-draining rivers of Ecuador and Peru, distinct from the Amazon-basin tetra genera that dominate the family. Its two species, R. altipinna and R. minor, run larger than the typical aquarium tetra, reaching roughly 4–6.5 in, and share a deeper-bodied, more robust build than the small schooling characins most aquarists picture -- one better suited to life in the swifter, rockier streams of the Andes' western slope than to still water.
Common names reflect that build: R. altipinna is known as the Highfin Rhoadsia, for its elevated dorsal profile, and R. minor as the Rainbow Characin. Neither is a regular presence in the aquarium trade outside specialist collections, and detailed care information is not well documented. Conservation-wise, both species are assessed as Least Concern, consistent with a genus that, while regionally restricted to Pacific-slope Ecuador and Peru, does not appear to face documented range-wide decline.