- The Filo Hua Hum river runs for 10 miles, one of the shortest rivers in the area, located between two lakes (Lago Nuevo and Lago Filo Hua Hum) inside the Estancia Tres Lagos. The Filo is a very scenic river to fish, mainly for big browns. Sight fishing with big dry flies, like attractors and terrestrials, is the best way to fish this river. It's highly recommended for experienced anglers that enjoy challenging fishing since the fish are spooky and fly presentation is very important. The best time to fish here is December to late January.