The Carrileufú is one of the connecting rivers threading through the Los Alerces National Park lake system, short and glass-clear, running between forested banks with the same painstaking transparency that defines the park's whole drainage. Fish here are well-educated by regional standards, holding in slower glides and along undercuts where a small CDC Emerger or Foam Ant, presented with a long leader and drag-free drift, draws a considered look rather than a reflex take. It's compact enough to fish thoroughly without a long day's walking, and a guide familiar with the park's access rules and current beat rotation is the practical way to approach it, since formal documentation for this stretch remains thin. Expect careful, technical fishing rather than numbers, and bring patience in equal measure to your leader spool.

• Volcanic glacial