Simple but effective as anyone who has fished a worm knows. The best way to fish this light pattern is when combined with split shot attached on the tippet material about 5″ above the fly to help tumble freely and swim in the current or bounced along the bottom.

The San Juan worm is a testament that sometimes the simplest flies catch fish, tied with a single strand of ultra chenille. Popular year-round, its also a great prospecting pattern on new water, during the winter months, or when water is high after a heavy rain and worms become dislodged from the bank. Dead drift in a double nymph rig, or as a dropper under a dry fly.