Fly Tying the San Juan Worm


The San Juan Worm is a Bow River staple and represents a midge larva, leech, aquatic worm, or an earth worm. The fly is unnessessarily contraversial.   It clearly represents active aquatic life no less than a caddis pupa, crane fly larva, or leech pattern and should be fished with a sporting confidence.  The fact that it so effective should be secondary.  We deliberated for sometime as to whether or not to post this fly...it seemed too simple to tie; however, quality fly tying is what we are about and this fly is meant to last if our techniques are followed.   It can be tied in many colours including olive, green, tan, brown, red, pumpkin, flouresent orange, black, etc.  Tie it in size 8 through 20 large gap or all-around hooks.  The hook shape, wire under-wrap, and the flexible chenille gives the illusion of life as it rotates with the current and tumbles across the river bottom.  Use it as an attractor pattern as a lead fly in a dropper combination when times are slow.  Tie two on at one time and fly fish what is fondly known on the Bow River as a Double Chico...great combo for after spring run-off fishing. 


  1. Standard Size 8 - 20 all-around or large gap hook
  2. Red #8 Thread 
  3. Brassie to Large Ultra Wire 
  4. Ultra Chenille 

 Tying Instructions  
 SJW_1.JPG Pinch the barb and wrap on a wire proportionate to the size of the hook.
 SJW_2.JPG Clip the wire with pliers...save you scissors.
 SJW_3.JPG Push the wire together with your thumbs. 
 SJW_4.JPG Attach thread at the rear of the fly to secure the wire in place. 
 SJW_5.JPG Attach the ultra chenille. 
 SJW_7.JPG Wind the thread forward between the wire wraps.  When you reach about half way, tie the chenille in place.
 SJW_8.JPG Continue forward with the thread and tie the chenille in at the eye of the hook. 
 SJW_9.JPG Put a dab of head cement on the underside of the thread wraps at the rear, middle, and eye of the hook. 
Carefully, singe back the chenille on each end of the fly.  The goal is to round off the ends.
 SJW_11.JPG Here is the finished fly.  Experiment with tying off the chenille at various angles to the hook and achieve the illusion of life.