Here is the fly pattern sheet for the Krystal Flash Mayfly Nymph – Seitz variation. He ties the fly to imitate BWO and PMD nymphs on the Crooked River, OR.

Krystal Flash BWO-PMD Mayfly Nymph |



Standard #16 – 18 nymph hook


Gold or copper – 2.3 mm for #16, 2.0 mm for #18


Black 8/0 Uni


Black Krystal Flash


Small gold or fluorescent orange wire


Black Krystal Flash

Thorax & legs:

Black Krystal Flash


Fluorescent orange 8/0 Ultra thread


  1. Debarb hook and slide on bead.
  2. Attach thread and wrap to hook barb.
  3. Cut 4 pieces of Krystal Flash 3″ long and attach to hook above barb, creating tail about 1/4″ long. Use 3 turns of thread to secure and an additional 3 turns immediately in front of material to firmly secure.
  4. Hold Krystal Flash up and wrap thread only to hook eye, creating a slight taper as thread is wrapped forward.
  5. Wrap the 4 strands of Krystal Flash forward to make body and tie off at eye.
  6. Separate Krystal Flash and use 2 strands for legs on each side of body. Use thread to secure in place.
  7. Whip finish and trim thread.
  8. Coat body with UV resin.


  • Add wire rib or use fluorescent orange thread for hot spot.
  • Substitute red Krystal Flash for black.
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