One of the most popular choices among beginning aquarium hobbyists, the Buenos Aires Tetra is native to South America. These fish can be found throughout the Rio Parana basin in Paraguay, Argentina and Brazil as well as in the Rio Uruguay basin in Brazil. This species of Tetra tends to inhabit a variety of bodies of water including streams, lakes, ponds and small rivers. The Buenos Aires Tetra has a metallic body with red fins and a black marking on the dorsal fin.