BASALT - Over the years, we have encountered many frustrated anglers who cannot figure out why the fish are continually refusing their flies.
Individuals often drop in, complaining that numerous fish would inspect their particular pattern and refuse it. They then explain that they changed flies several times and the fish repeated their inspections still refused the fly most of the time.
It's usually while dry-fly fishing or sight nymphing that one bears witness to these annoying recurrences. Getting refusals suggests the drift of the fly is good. Lightening up on tippet size is all that's likely needed.
Typically, if your fly is being refused at the last moment, the trout likes what it sees from a distance. However, upon closer inspection, there are three key things that cause trout to refuse a fly: micro drag, a fly that is one size too big or too small, and tippet that's too big.
Micro drag is a slight imperfection in the presentation caused by small subtleties during the drift; usually only the most selective fish will notice. Most anglers try flies of different sizes in their efforts to figure out the issue, but usually, if an angler consistently changes flies and fish consistently refuse the offering, the problem can be attributed to tippet that's too large in diameter. The simple solution is to drop down in tippet size. Sometimes dropping down by one size is enough, while other situations may require dropping down several sizes.
Tippet size is influenced by several factors, including the size of the fly, water clarity, water speed and the temperament of one's quarry. Generally, the larger the fly, the larger the tippet can be. Heavy, fast or discolored water usually enables the use of slightly heavier tippets than if conditions are low and clear.
You will also encounter fish that can be leader shy or, on more heavily fished waters, that are more selective and cautious. With these thoughts in mind, adjust your tippet accordingly. You may be able to fish a size 12 green drake tied to 4X on a big freestone river like the Roaring Fork, while you will need 6X when fishing that same fly on a tailwater like the Fryingpan.