Just to be sure, I checked with the Idaho DNR about utilizing dried eel skin in a pattern and fishing in "Fly fishing only" water.
I got this response today:

"From: Parrish,David Sent: Monday, April 08, 2013 11:24 AM
To: IDFGINFO
Cc: Wooten,Greg
Subject: RE: WEB SITE - email



Byron,

In ?fly-fishing? only waters, you cannot use fish, fish parts, or other organic matter as part of your fly pattern. Therefore, dried eel skin would be illegal in a ?fly-fishing, only? water.

I understand the eel skin is more for presentation rather than an attractant, but current rules prohibit bait in fly-fishing only waters. Eel skin falls under the definition of bait.

Dave Parrish
Sport Fishing Program Coordinator