Lay a thread base to the bend and tie in a short tail of bright green bucktail, half a shank length long.
Tie in the silver tinsel rib, then dub a slim pinkish-white body forward to the 80% mark. The pink body carries the rainbow's lateral stripe through the whole fly.
Rib with 5-6 evenly spaced turns of silver tinsel and tie off.
Tie a sparse pink bucktail throat under the shank, reaching halfway to the hook point.
Build the wing in sparse layers to the tail tip: white bucktail first, then pink slightly blended into it, then green, echoing a rainbow parr's coloring from belly to back.
Top with a few fibers of badger hair for the dark back, form a neat head, whip finish, and lacquer.