The San Juan Worm in red is an essential sub-surface trout fly that most anglers have in their nymphing box. With so many variations of this fishing fly, you can’t go wrong with the original pattern that started it all. Best when fished alongside some split shot, this trout fly bounces along the bottom and draws bites from fish big and small. Oftentimes, the simplest patterns are the best fishing flies. That rule certainly applies to the San Juan Worm, if you haven’t fished it already, please do.