The Rio Iaco is a significant tributary of the Rio Purus, flowing through the state of Acre in the western Brazilian Amazon. This remote and biodiverse river system is characterized by its meandering, tannin-stained waters that flow through dense rainforest. As a lowland Amazonian river, it experiences dramatic seasonal fluctuations in water level, which fundamentally shape the fishing environment and fish behavior. The riverbed consists primarily of sand and silt, with submerged woody debris and overhanging vegetation providing critical structure. Fishing here is a wilderness experience, offering anglers the chance to target iconic Amazonian gamefish in a pristine and challenging environment.