The Simi Seal Leech: A Minimalist Fly That Fools Steelhead
Some fly patterns earn their place in a box not because they're elaborate, but because they work. The Simi Seal Leech, which she calls her semi seal dubbing leech, is the favorite leech pattern of Ari Capotis, who guides as Keystone Fly Girl in Pennsylvania's Steelhead Alley. It's approachable enough for tiers of nearly any skill level.
In a recent tying demonstration with FishUSA, Capotis walked viewers through every step of constructing this deceptively simple leech pattern, sharing not just technique but the philosophy behind why less material often means more fish. What follows is a complete guide to tying the Simi Seal Leech — along with the insights that make it genuinely effective on the water.
Why This Pattern Works: The Case for Sparse Flies
Before picking up a bobbin, it's worth understanding what makes this fly different from the heavily dressed streamers that dominate many steelhead boxes. Capotis is direct about the problem with overdressed patterns — even beautiful ones.
"Especially here in Steelhead Alley, there's a lot of overdressed flies that people are fishing. They look great to us, but there's just too much material on the hook, and there's something about it that the fish can tell."
The Simi Seal Leech sidesteps this trap by relying on the natural movement and translucency of the dubbing material rather than sheer volume. The result is a slender, flowing profile that suggests a minnow or leech without overwhelming the hook. In low, clear water conditions — often the most challenging scenarios for steelhead anglers — this subtlety becomes a distinct advantage.
"Low, clear water — this fly is pretty deadly. I don't know if it's just that it's the impression of a minnow or what, but see how it's not super duper bulky on the hook shank. I think that's a big component of it."
Materials You'll Need
One of the appeals of this pattern is its short material list, and the main ingredients are available on the FishUSA website.
The Hook: Voodoo Jig Heads
Capotis's hook of choice for this pattern is a Voodoo jig hook — a practical selection that comes with the bead weight already integrated into the hook itself. For tiers who regularly batch-produce flies, this is a meaningful time-saver.
"If I'm in a pickle and I need to tie a bunch of these, they're super handy because we already have the weight built into the hook. Instead of having to buy a hook and then a bead separately, it's all connected."
The Dubbing: Semperfli SemperSeal
Capotis uses Semperfli SemperSeal, a seal dubbing she describes as very similar to Arizona Simi Seal dubbing but with slightly longer fibers, so she takes a little more time when making the dubbing loop with it.
When building both the tail and the body, the same dubbing material is used throughout, which keeps the pattern cohesive and simplifies the material list even further.
Thread: UTC 70 Denier
For thread, Capotis opts for UTC 70 denier — a finer choice than some tiers might expect given the size of the jig hook. The reasoning is intentional and ties directly into the philosophy of sparse, effective flies.
"I like to have an understated look to my flies, so that's why I like to use 70 denier thread for this fly in particular."
That said, because these jig heads are larger, you can absolutely go with a heavier thread.
Additional Materials
Rounding out the material list: low-tack dubbing wax to help the dubbing adhere during the loop-building stage, Sally Hansen Hard As Nails for finishing the head, and a standard whip finish tool. A dubbing pick or bodkin will also prove useful during the finishing stages for teasing out material and applying the Hard As Nails precisely.
Step One: Setting Up the Hook and Building a Thread Base
Before any material touches the hook, proper setup in the vise is critical — especially if you're working with a rotary vise, which Capotis recommends highly for streamer tying.
"Make sure that you have the hook in here appropriately — nice and even — so I can work right across the hook shank. It's not in here at a weird angle."
Once the hook is seated correctly, attach your thread and work it back toward the bend of the hook to establish a solid thread base. This base isn't decorative — it serves a functional purpose. Without it, the tail material has a tendency to rotate or slide around the hook shank during tying, which can compromise both the look and the action of the finished fly.
Work the thread back to approximately the barb of the jig hook before stopping. This is your starting point for the tail.
Step Two: Tying In the Tail
The tail on a leech pattern establishes the fly's overall silhouette and contributes significantly to its movement in the water. With the Simi Seal Leech, the tail length is a matter of personal preference — but Capotis offers a practical reference point for tiers who are unsure where to start.
"When I'm making a tail for my flies, I usually like to use the shank of the hook as a gauge for length."
Pull a small amount of SemperSeal dubbing and try to align the fibers as evenly as possible. The material doesn't need to be perfectly uniform — in fact, a little irregularity contributes to the fly's impressionistic character. Use a pinch wrap to secure the material to the hook shank, keeping your thumb and index finger tight around the thread until the material is positioned correctly, then cinch it down with additional wraps. Trim any excess material in front of the tie-in point to keep the body area clean.
Step Three: Building the Body with a Dubbing Loop
The dubbing loop is the technical heart of this pattern and the step that deserves the most attention and patience. A well-executed dubbing loop produces a full, brushy body with fibers that radiate outward and move naturally in current. A rushed one results in a lumpy, inconsistent body that neither looks nor fishes as well.
Form the loop by wrapping the thread around the hook shank a couple of times, then walking the thread forward toward the jig head. Before loading the loop with dubbing, apply a thin strip of low-tack dubbing wax to one side of the loop. This wax acts as a temporary adhesive that keeps the dubbing in position as you spin and wrap.
"You don't need to be liberal with the wax, for two reasons: it's very sticky, and it's got a little bit of a yellowish tint to it. If you're a little overzealous with the wax, you will see that — especially when this fly gets wet."
Stack the dubbing material into the loop carefully, working it in evenly from top to bottom. Use the excess material trimmed from making the tail — nothing goes to waste with this pattern. Once loaded, attach a dubbing hook or similar tool to the bottom of the loop and begin spinning it to twist the fibers tightly together. Consistency matters here: choose a direction and stick with it throughout.
"Less is more. You don't want to be using way too much because you can always add more. If you rush this, you're really rushing your fly — and you're doing yourself a disservice."
Step Four: Wrapping the Body
With the dubbing loop spun tight, it's time to wrap the body forward toward the jig head. If you're working with a rotary vise, this stage becomes particularly fluid — you can rotate the fly while keeping your wrapping hand relatively stationary, which gives you excellent control over the placement of each turn.
As you wrap, use your free hand to continuously brush the longer dubbing fibers back away from the direction of wrapping. This prevents the fibers from getting trapped under subsequent wraps, which would flatten the body and reduce movement. The goal is a body with fibers that splay outward in all directions — bushy, lively, and full of texture.
Once you've reached the jig head, tie off the loop with a series of thread wraps in front and behind, being careful not to accidentally clip your bobbin thread when trimming. A small dubbing noodle twisted from leftover material can be used to build up a neat collar just behind the bead head, giving the fly a finished, polished look.
Step Five: Finishing Touches and the Whip Finish
A clean finish is the hallmark of a well-tied fly, and Capotis doesn't cut corners here. She recommends a double whip finish for added durability — a small investment of time that can significantly extend the life of a fly during a hard day on the water.
"I like to have flies for more than a few fish, and I find that adding the extra whip finish on it is helpful."
For securing the thread head, Capotis turns to Sally Hansen Hard As Nails, the nail polish. Her technique for applying it is notably precise: rather than using the included brush (which she avoids entirely), she opens the bottle and uses the tip of a bodkin to transfer a tiny amount directly to the thread wraps.
"If you use too much of it, you'll actually see that there's a dark hardness where you applied it, and I don't like that look. So I'm very sparing with the Sally Hansen Hard As Nails."
Once the head is finished, use a dubbing pick to tease out the body fibers and give the fly its final, slightly disheveled character. Capotis keeps the fibers a little longer toward the back of the fly and trims them down a bit up front.
On the Water
Capotis fishes these flies all the time, but she says that in low, clear water this fly is pretty deadly. She urges tiers to stay sparse, use thinner thread than they otherwise might, and give Hard as Nails a try after the whip finish.
A Note on Fly Tying Philosophy
Throughout her demonstration, Capotis returns again and again to a theme that extends well beyond this single pattern: fly tying, at its core, is a creative and personal pursuit. Recipes and techniques provide a foundation, but they're not law.
"Within all of this, when we're fly tying, for most of us this is really just going to be for enjoyment. It's more or less adults' arts and crafts. I'm giving you the basic recipe — but go ahead and alter it as you see fit."
Change the color, adjust the tail length, try a different dubbing: the core structure is forgiving.
And if you fish Steelhead Alley, where Capotis sees a lot of overdressed flies, it might be time to make room for something sparser.
