I have deep qurrays that have alot of 5 to 8 pound rainbows in it.I've fished them quite a few times with flys no strikes but each time see rings and big swirles.But do'nt see any hatching insects.Any help please.I do know of only a few taken 5 to 8 pounders taken on only worms.This has been diiving me crazy for the last few years.I've almost converted back to bait fishing a few times (HELP PLEASE)
I don't know what part of the country you are in. I have had similar problems and have had fairly good luck with a san juan worm pattern. The San Juan is a tubifex worm. They are pretty common in the rocky mountain area. It is probably the easiest pattern to tie and the one that consistently catches big fish, all times of the year. I tie them in bright red and brown. The brown San Juan's look a lot like a small earth worm and I have always suspected trout sometimes take them for just that.
I fish them deep with split shot on the leader about 18 to 20" ahead of the fly, you could use a heavy nymph as a dropper too. I use a strike indicator as well. the strike indicator slows down the travel time in fast water and gives a more drag free drift.
I have had luck with this pattern in lakes, but usually at the inlet. This is usually my standby pattern for deep, fast rivers.