Rio S?o Francisco, at Minas Gerais – Brazil, was the location for this fishing trip. We were targeting “Matrinx?” fish (Brycon orthotaenia) on lightweight fly rods. The“Matrinx?” is an endemic fish of this basin. We were fly fishing with Chernobyl Ant flies and a variety of other big terrestrial fly patterns. Fishing for “Matrinx?” fish is, in many respects, similar to fishing for trout. Dead drifting the terrestrials on the surface while maintaining good line control is required. Accurate and pin point casts close to the structures where the Matrinx? reside is also required, if you desire to have one of these hard fighting fish on the hook. The reason for needing casting accuracy around the structures is because this same river holds huge Gold Dorado (Salminus Franciscanus) which are also an endemic species of this basin. The Dorado are always on the prowl for and easy Matrinx?s meal. Therefore, the cast needs to be just right and the fly needs to be presented perfectly in the feeding lane because the “Matrinx?” will not chase the fly and make itself prey to the bigger fish in the river. When targeting “Matrinx?” we use 6 weight fly rods, floating lines, a short piece of 6.6 lbs. fishing wire, and 9’ leaders. On this specific trip, I fished a Sage Bass Bluegill fly rod which is a perfect tool for the job (less back casts and accuracy over the structures). Fishing for Matrinx?s is a hell of a lot of fun and technical fishing. I think that anyone that likes this kind of fishing should try it at least once. Brazil is not only about peacock bass.