Fly Tying

How to Tie the 20 Incher Stonefly Nymph Pattern

Apr 26, 2019 · 4 min read
Chandler CransBy Chandler Crans
Chandler Crans
Chandler Crans

Chandler Crans is a fly fishing expert and a former guide in Alaska. Whether he's reviewing the latest rods and reels, writing about where to fish,...

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How to Tie the 20 Incher Stonefly Nymph Pattern

Tips for tying a 20 Incher Stone Fly Nymph Pattern including a materials list, instructional video, and much more. Improve your fly tying skills here.

The 20 Incher Stonefly Nymph is a popular pattern for any trout water. The 20 Incher is a great early season searching pattern and works well as the point fly on any nymph rig. Whether you're targeting finicky trout in the western US or sight fishing in New Zealand, the 20 Incher is a great fly to have in your arsenal. Scroll down to the bottom to browse through the materials for this fly!

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20-Incher stonefly nymph fly-tying hook with black bead head and silver wire ribbing on olive curved shank in vise

Step One:

Wrap the lead wire and seat it behind the bead toward the eye of the hook. The lead wire will help the nymph sink quickly. It also helps develop proper body proportions of a Stonefly.

20 Incher stonefly nymph with black bead head, copper ribbing and brown tail clamped in vise, fly tying tutorial

Step Two:

Tie in the Goose Biots for the tail. When tying these in, you want to make sure that they face opposite ways so they curve out to get a nice splayed tail. Sometimes creating a little thread bump to split the Biots apart works well. Cut the Biots just about half the length of the hook shank. Catch the Biots with a loose wrap to get them on the hook and then position them. When you're satisfied with their positioning, tie them down.

Beadhead 20-inch stonefly nymph with brown body, copper wire ribbing and black bead clamped in vise for fly tying

Step Three:

Tie in the copper wire. Tie it right behind the lead and keep it on one side of the hook shank. Use the thread to wrap all the way back to the Biots to firmly anchor the copper wire. After it's anchored, bring the thread back up to the lead wire.

Olive peacock herl stonefly nymph on hook with black bead head, silver ribbing and copper legs in fly tying vise

Step Four:

Tie in the Peacock Herl. For a hook this size, we used four or five herls. Tie them in right behind the lead, wrapping the thread back to the tail. Finally, return the thread to the beginning of the lead.

Stonefly nymph fly tying: olive-green chenille body, brown split tail and black bead head secured in vise

Step Five:

Wrap the Peacock Herl. Because Peacock Herl is a pretty fragile material, twisting the herls as you wrap them makes the collection of herls a little stronger. Wrap the herl almost up to the bead head. Tie each individual herl down and back. Then, cut or break off the excess herls.

Black bead-head stonefly nymph with olive peacock dubbing, gold ribbing and brown tail clamped in vise — fly fishing pattern

Step Six:

Counter wrap the copper wire. The wrapping of the copper wire strengthens the herls and provides a segmented appearance to the fly. Wrap the copper wire tightly. Tie the copper wire off with a couple of wraps then helicopter the wire to break it off.

20-incher stonefly nymph fly with long mottled brown feather wing, slim dubbing body and black beadhead clamped in vise

Step Seven:

Tie in the wing case. Choose a piece of pheasant tail that's about the width of the hook gap, maybe a little larger. Tie it in right on top of the hook shank. There are two sides to the treated pheasant tail, light and dark. Tie the light side up so when you fold the wing case over, the dark side will show. After catching the wing case with some loose wraps, position it then tie it down.

20 Incher stonefly nymph fly with mottled feather tail, tan dubbing body and black bead head held in tying vise

Step Eight:

Dub the body. Grab some dubbing with your thumb and forefinger and work it onto the thread. Wrap the thread from mid-shank up to just behind the bead head. The dubbing should be nice and 'buggy' and look like insect legs so it will breathe well in the water.

20-incher stonefly nymph on vise with mottled tan-and-black feather tail, tan dubbed thorax, black bead head

Step Nine:

Tie in the legs. Create a little V with the Coq De Leon so you can tie the legs in on either side of the body. Fix the legs loosely with a single wrap and measure the length first before you fully tie them down. Make sure they're evenly distributed. Tie them down and cut off the excess material.

20 Incher stonefly nymph fly with black bead head, olive peacock dubbing body, brown tail and soft hackle in vise

Step Ten:

Pull the wingcase over the body. After you pull the wingcase over, tie it in just behind the bead head. Make sure the pheasant tail is nice and wide and flat, not bunched up. You'll see it'll kind of spread the legs out as well. Again, just a loose wrap over the top, position the wingcase where you want it, then tie it in. Take some pretty sharp scissors and cut the excess pheasant tail. Finally, throw a whip finish.

Olive green 20-incher stonefly nymph with gold ribbing, tan dubbing thorax and black bead head in vise — fly tying

Step Eleven:

Pick out the dubbing underneath the fly. Picking the dubbing out and combing it to either side makes the fly profile wider and flatter like a Stonefly.

Olive peacock-dubbed stonefly nymph with tan fur thorax, black bead head and gold hook, fly fishing pattern

And that's the 20 Incher Stonefly Nymph. Be sure to tune in during the next few weeks as we tie the Royal Wulff and a Zonker Streamer.

Questions?

Give us a call here at the shop at (888) 413-5211 or email us anytime at [email protected].

Materials:

Hook: Daiichi 1270 Multi-Use Curved Hooks

Wire: Hareline Spooled Lead Wire, UTC Brassie Ultra Wire

Tail: Hareline Stripped Goose Biots

Body: Hareline Strung Peacock Herl

Underbody: Spirit River Squirrel Blend Dubbing

Legs: Hareline Coq De Leon

Wingcase: Hareline Ringneck Pheasant Tail Feathers (treated).

Chandler Crans
Written by

Chandler Crans

Chandler Crans is a fly fishing expert and a former guide in Alaska. Whether he's reviewing the latest rods and reels, writing about where to fish, or helping a first-time angler pick the right fly line, Chandler combines real guiding experience with deep product knowledge and a genuine love of being on the water.

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