Who hasn’t seen a Mickey Finn? The fly has a history that goes back at least 100 years. It has enjoyed staying power for the simple reason that it catches fish. Consequently, it is a fly that you’ll find in assortments sold to beginners as well as on the vises of seasoned experts.

Living in New England, I sometimes feel obligated to fish the Mickey Finn. Even the most contemporary guidebooks list the  yellow-and-red streamer as one of the key patters for fabled brook trout waters in New Hampshire and Maine. And the fly has produced for me. But it has primarily been productive on those larger rivers of renown. Most of my fly fishing takes place on smaller creeks and pressured streams. The Mickey Finn hasn’t been as productive for those selective, finicky fish.

Instead of trying to force-feed trout a fly that they should be eating (if they knew what’s good for them), I spent some time deconstructing the pattern. Why does it work? What is essential? And, most importantly, how can I adapt it to the fish and scenarios I most frequently encounter?

This is a pursuit that anyone, with any amount of fly tying skill, should consider. Most flies are only a variation on a theme. Innovation is often only modification. And a slight alteration to a famous pattern might mean more fish for you.

Here’s what I did to the Mickey Finn:

Hook: For smaller streams, I choose a 2X heavy wire, 2x short egg hook. I like how the weight of the hook balances out the rest of the materials, Also, the weight in the bend facilitates a “level sink” in slower water.  A size 8 is just about perfect, but I tie them in 6 and 10 as well.

Thread: I like black 8/0 thread. I’ll tie it just past the point where the hook bend begins.

Body: Traditionally, the Mickey Finn calls for oval and flat tinsel. To save time, and because the hook is already bulky, I only use flat tinsel. I do make sure that it covers the thread completely between the tie-in point and the body.

Wing: This is the biggest alteration. Instead of yellow and red bucktail or calftail, I use yellow bucktail and red marabou. The bucktail gives the fly a silhouette and length. Marabou gives the fly body. Moreover, marabou is a material that can be fished passively. It will move on its own in even the stillest waters. I tie the marabou in first on top of the hook. I want the tips of those feathers to extend just past the bend of the hook. The bucktail ends up being about twice the length of the hook. Once I position it, I’ll roll it  in my fingers so it surrounds the marabou and the hook shank.

Head: When I think traditional streamers, I think big thread heads. I like to give my Mickey Finn this treatment. Then, I apply fluorescing UV resin. This is another simple step that creates a passive attracting opportunity.

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Nothing remarkable. Nothing revolutionary. But a fly that catches trout.

I’ve made similar adaptations to wooly buggers, hares ear nymphs, and traditional dry flies. Some of them have to do with my tying skills (or lack thereof), while others are my attempts to build a better mousetrap. Every time I learn something: about my local water, the fish, and my approach to fly fishing.