North of Coyhaique, the Mañihuales runs through quieter, more pastoral country than its neighbours — open valley, scattered estancias, and a glacial-volcanic river that carries good flow without the crowds of the Simpson. Brown and rainbow trout respond well to the same big terrestrial patterns that work across the region — foam hoppers, Chernobyl Ants, Chubby Chernobyls — worked tight to grassy banks and undercuts through the summer months. It's a river best fished with someone who knows the access points, since much of the bank runs through private land, but the reward is water with a genuinely wild, unpressured feel and fish that haven't seen a fly shop's worth of flies before yours.

• Volcanic glacial