The red San Juan worm is a great trout attractor pattern. This pattern is best fished in a single or double nymph rig and can be especially effective after it rains. The red San Juan worm can catch fish on small creeks, freestone rivers, and large tailwater rivers. An overall fish catching machine the red San Juan worm is a good fly to have in varied sizes for all anglers. The red San Juan worm should always have a spot in the fly box.