Keith Fulsher's Thunder Creek Minnow is a fly with a Wisconsin origin that is fairly well known but I'd say much less known than the pattern should be. I mean, there is a book about the Thunder Creek style so they are certainly not unknown but it sure seems that it is an underutilized style of fly. I'll be the first to admit, it is not a style of fly I fish often despite the fact that I enjoy tying them. I also enjoy the flexibility of the pattern - the fly can be tied to imitate a number of slim minnow species.
I post the style mostly because it is a Wisconsin based fly. The story goes that Keith Fulsher was a New Yorker - born in Wisconsin - that tied and tested the flies on Wisconsin's Thunder Creek, which as near as I can tell is an Oconto/Marinette County stream complex. I say, as near as I can tell since this is my internet research - his is one of the fly thing books I don't own (yet).
To tie them is pretty straight forward - it is a reverse tied bucktail fly where the butts are covered with thread wraps and they become the head.
Pattern Overview - This is my interpretation - patterns are like guides, not cookbook recipes, IMHO. Use what you have on hand and what suits the fly you want to tie. I think that the original pattern would be in a bit different order than I tie them. I tie the tinsel body first then the flash and the body/wing/head/whatever you want to call it.
Hook: a 6x long with preferably a ring eye (the flies below are a standard down eye hook, it is what I had).
Thread: Whatever you like but I used white in a small diameter (14/0 Bennichi - again it is what I had). Original pattern calls for red to mimic gills but you can make the underside red with a marker or get fancy and add some hair or feather fibers to mimic the gills. The simplest way to accomplish this is to use a marker to color four inches of your thread before you whip finish the fly.
Body: Tinsel of your choosing; generally a silver, gold, pearly type tinsel is best. Maybe black if you want it to look like a lateral line. I used flat tinsel but I saw others that used round or oval tinsels. Use what you have and like.
Flash: Krystal Flash, I double-over a few strands (2-5) and then trim them after the wing is done. Trim each individually so they end at different places on the fly.
Underwing / Belly: Bucktail, almost certainly white but if not white, some other light color to get the countershading effect when you add a darker top. This it tied in so that the tips are facing forward (over the hook eye). Estimate the length so that the head is about 20% of the hook shank and the wing is as long as you would like it. The original have the wing not much longer than the hook shank. I tie most of mine considerably longer than that.
Overwing / Back: Bucktails, colors to match the minnows you are tying to imitate. Since it is reverse tied, if you are using more than one color for the back (overwing), tie in what you want to be the top of the fly first and then tie in what you want to be along the lateral line next. Mr. Fulsher recommended hair from the lower half of a bucktail which means he was looking for hair that had a little flair to it. Use a second bundle of white bucktail that you tie in as the last clump in the overwing if you want a larger light section - like many of our shiners have.
Head: Epoxy or UV resin. The original pattern would have you paint the eye after epoxying the head and then coating the eye with another coat of epoxy. I used eyes that I had bought, either flat eyes or 3D epoxy eyes and coated the head with a thick UV resin. After curing the head so it was relatively smooth and the eyes were well secured, I then coated it with Loon's UV Flow to get a smooth, shiny head without tack.
Other Notes: Pull the hair back tightly, it will make a much smoother head when covered with epoxy or resin.
What I like about the pattern is that it is simple and effective and the pattern is a blank canvas where you can change the color and to a lesser extent, the shape of the fly, quite easily. Personally, I like the hair to have a decent bit of flare to it so that when the fly is dry, it looks significantly wider than the minnows I am representing. I think this allows the bucktail to move a little more in the water when it is wet and being retrieved.
Some Variations to Try:
Blacknose dace are a common minnow in slightly warmer trout streams (colder trout streams generally have few if any minnow species) and are well represented by the Thunder Creek style of flies. The belly is white, the top of the fly is a dull brown, and the lateral line is black and very distinct.
Shiners are again common in many warmer trout stream reaches. These fishes tend to be, well, quite shiny. To imitate these, I tend to use mostly white or a very light gray bucktail I have for 90% of body and just a few darker fibers for the top of the fly's back. If you look at most shiners, the backs will be a mottled black or dark gray with some having olive and purplish highlights.
Adding feathers along the lateral line is something I've seen more lately with this style of fly. It can give a nice barring or if using a black hackle for a distinct lateral line.
Mixing bucktail colors is an effective way to mimic fishes that have irregular or mottled appearances. To do this, I will take two or more colors and randomly stack them in my fingers or put them in a much too large hair stacker and run a bobbin through them to mix the colors together. There are some cases - like the blacknose dace - where fishes have distinct color separation along the body but for many fishes, their have a much less distinction like in stoneroller minnows or the tops of shiner species backs. Often a few - 10-25% of the total number of fibers in the back - darker bucktail fibers will provide a fairly effective mottling effect when the fibers are blended.
Brown Trout are probably the most common prey of piscivores in the trout streams near me because they are simply too cold - or there are too many piscivorous Brown Trout - for minnows and small suckers to thrive. For smaller Brown Trout, the Thunder Creek style is an effective imitation. You certainly tie them with a yellow belly and a brown back but you might get more creative and use the bucktail mixing above to create a belly that is mostly yellow with a bit of white, black, brown, red, and/or blue and a topside that is more brown with some yellow and maybe some of those other colors found in Brown Trout.
Tying materials - while the pattern was devised as a bucktail pattern, you can do the same thing with synthetic hairs, Arctic Fox and other furs, and marabou. You will get quite a different result but why not experiment and see what works for you. It is a great platform for improvisation. Tie them in colors to match your local forage fishes, be creative. Get them wet to see what they will look like when fishing them.
I am not the best at providing patterns since I rarely follow them. Below are some sources if you want to tie the fly more authentically.
Resources and sources for patterns: