Monoculus Peacock Bass are found living in the main stem of the Amazon River, mid to upper areas of the Rio Negro and in surrounding tributaries of both rivers. Monoculus Peacock Bass are distinguished visually by short vertical bars that do not extend below the lateral line and a long horizontal bar originating at the base of the pectoral fin. Most Mono Peacocks found in the hobby today are captive bred from Asia. Very few are imported from the wild.