The river microhabitat where Poecilocharax callipterus was discovered. This species is found among vegetation accumulating along the riverbanks, such as the aquatic grass in the lower-left corner of the photo. P. callipterus lives in blackwater rivers, which are tinted by leaves and other organic matter that accumulate at the bottom of the river.
Smithsonian’s National Museum of Natural History researcher Murilo Pastana and his colleagues have discovered and described two new species of Amazonian fish—one with striking red-orange fins and the other so small it is technically considered a miniature fish species—in a paper published today, May 16, in the Zoological Journal of the Linnean Society. Both species inhabit waters located at the bleeding edge of human encroachment into the Amazon rainforest roughly 25 miles north of the Brazilian city of Apuí.