Last Friday in Ontario, Canada I caught two rainbows on a Lightnening Bug - thought it was the answer, then nothing. Switched to a Sawyer/Wulff grey nymph (NO FLASH) and caught 8 more. The day was sunny a bright and the water was clear. A couple or 3 more on a wet fly (dark/dull) variety. My buddies did not use flash either and caught about 12 each also.