Re: dry fly presentation?
Sometimes fish are just finnicky! They won't take anything even though they are obviously feeding on something. My go-to fly is the Adams#16 dry. I try that usually first. If that doesn't work I have gone down to tieing on some ^X tippet to my line and float a#20 Griffith's Gnat or #18 or 20 midge and that has worked sometimes. They normally are always are feeding on midges. If they are just sipping from the surface, try the smaller flies. Or try to float something in the surface like a midge emerger. Sometimes it's time to go find another fish because if they become stubborn, you can work all day on him and still not catch him. Then you get frustrated and think you are a poor fisherman. Remember, they make a living eating and swimming and they know what's real and what isn't. This is called 'fishing', not catching! Frustrating sometimes? Yes! Rewarding when the fish is on? Absolutely! Keep at it!
"I fish because I love to; because I love the environs where trout are found; because trout do not lie or cheat and cannot be bought or bribed or impressed by power, but respond only to quietude and humility and endless patience...because only in the woods can I find solitude without lonliness..." Robert Traver 1964 (Judge John Voelker)