Re: stocked trout
It has been my personal observation that recently stocked trout are obsessed with bright orange objects. For example, the local fly shop sells a "steely stone" which is essentially a fluorescent orange colored pheasant tail nymph. It kills for the first 2 weeks after the state(s) stock the local streams. My personal favorite is a fluoresecent orange silicone egg. I have fished a pool of trout stocked 2-3 days prior and spent more time removing barbless hooks than I spent watching a fluorescent orange silicone egg drift through the pool.
Absent either of those two flourescent orange flies or another close substitute I have been known to overhand knot a small bit of fluoresecent orange "egg" yarn in the tippet or leader about 10" above the first wet fly. When I use the overhand knotted fluorescent orange yarn I get more than a few what I refer to as "head shake and off" which I suspect is a trout who grabbed the yarn and caught a bit of floss on his/her teeth so couldn't spit the yarn immediately. I also get a few fish foul hooked on the first fly which suggests a bite at the yarn followed by flossing tippet through the trout's mouth.
If all you have is stocked trout (recent stocked at that--less than 2-3 weeks since stocking) give fluorescent orange a try.