Re: Worm problem!
Are your flies deep enough? Can you feel your fly/flies bouncing off the bottom? Also, what is the water quality? Are there mayfly, stonefly, and caddis hatches? Flip over some rocks and see what you can find. Have you tried any midge patterns? Midges are one of the most prevalent insects. Where I fish (midwest) my go to pattern is a zebra midge or a blood midge.
Also, since they are stocked fish, look for a pattern that imitates the pellets they are fed. Search "Trout Pellet Flies" and pick one you think will work. I heard of people using BH prince nymphs with brown vinyl ribbing material for the body for stocked fish.
Anyway, Some food for thought and I hope this helps.