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Isonychia Nymph Pattern & Tying Instructions

Fly Tying Recipe: Isonychia Nymph
3X-long nymph hook (e.g.Daiichi #270), size 12.
Black, 7/64-inch.
.020 lead-free wire, 15 wraps.
Dark Brown, 70-denier or 8/0.
Gold Ultra Wire, size Brassie.
5 dark-brown pheasant-tail fibers.
8-10 dark-brown pheasant-tail fibers.
Dark maroon rabbit and hare’s-ear dubbing, blended.
UV Clear Fly Finish, thick.
Rough out the thorax to create legs.
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Video Transcript:

This is a weighted Isonychia Nymph. Like many of the patterns I tie, it’s kind of a mash-up between a pheasant tail and a hare’s ear in terms of materials and technique.

For a hook I like a Dai-Riki #270 in a size 12. Start by mashing the barb on your hook. Although it’s always a good idea to do this before you start tying, here it’s required to allow a 7/64” black bead to slip onto the hook. small hole first. Even then, a little coaxing may be needed to get it around the bend.

With the bead in place behind the hook eye, get your hook firmly secured in your tying vise. To get the fly down fast to where the fish are, .02 lead free wire is used. To conserve wire, while holding the spool in your right hand, clamp the very end to the near side of the hook with E-Z hackle pliers and start taking wraps forward. Fifteen or so is plenty. Most of the time you can break the wire off clean with just your thumbnail. Pull the wraps rearward to expose some area behind the bead and then, with a small brush or bodkin, apply a bit of Zap-a-Gap to the hook between the wraps and the bead. Slide them forward, up into the back of the bead where the adhesive will lock them in place. Next, finish curling that extra bit of wire around the hook shank.

For thread, I’m going to load a bobbin with 70 Denier Ultra thread in dark brown. Start your thread on the hook immediately behind the weight and, after a few wraps, snip or break the tag end off close. Then build up a little ramp and thread dam to ease the transition up to the weight.

Brassie-sized gold Ultra wire will be used to rib the fly, about a 3 inch piece is all that’s needed. Attach one end of the wire to the near side of the hook, so it butts up against the weight. Take thread wraps rearward, securing the wire to the near side. Go all the way back to above the hook barb.

Select a dark brown pheasant tail feather with long fibers and pull down 5 or so perpendicular to the stem and then strip them off. This should keep the tips aligned. Snip the curly butt ends off square. Check to make sure the tips are still properly aligned. Measure to form a tail a little more than a hook gap in length, and with a pinch wrap, secure the fibers to the top of the hook shank. Pull them rearward and make 2 complete turns just around the hook shank then one more around the fibers to really lock them in place. Get hold of the pheasant tail fibers and, starting right at the base of the tail, begin making adjacent wraps behind the thread. Keep on going until you’re about 2/3 of the way up the hook. It can be a little tricky holding on to the short butts while you tie them off with a few turns of tying thread. Once they’re secured snip the excess butts off close.

Now get hold of the wire and pass it under the hook shank so it doesn’t jostle the tail fibers and start making open counter-wraps over top of the pheasant tail body. Go around the wire with your tying thread to reverse the direction of thread wrap. Next take counter-wraps of thread to lock the wire down tight. Once it’s secure, again use the wire to change the direction of thread wrap back to normal. You can then helicopter the wire to break it off close. Take a few more thread wraps to ensure nothing will work loose.

From the same dark brown pheasant tail feather, this time strip 8-10 fibers free from the stem. You don’t need to worry about keeping the tips aligned. Snip the curlies free from the butt ends and then secure those butt ends to the top of the hook shank just behind the eye. Use your thumb to flatten them out and continue taking thread wraps rearward to the abdomen of the fly.

For the thorax, I’m using a custom dubbing blend of rabbit and hare’s ear that’s a dark maroon in color. A variety of dubbing materials will work here as long as it includes some spiky guard hairs that can be roughed out to look like legs. Wrap the dubbing noodle to build up an ample thorax and end with bare thread just behind the bead. Pull the pheasant tail over to form a substantial wing case and anchor it with a couple tight turns of tying thread. Lift the butts up and take a single wrap under the fibers and then a few more over top. You really want to make sure these fibers are locked down firmly before you reach in close with your tying scissors and snip the butt ends off.

Do a 5 or 6 turn whip finish to secure your tying thread and then snip or cut it off close.

At this point you could apply head cement to the wing case and wraps but I’ve found a coating of thick UV resin looks and performs much better. You don’t need much, just enough to coat the wing case, the top of the thread wraps and out onto the bead. A bodkin can be used to ensure complete coverage. Once you’re satisfied with the resin placement, get hold of your UV torch and give the resin a good shot of UV light. After a few seconds it should be dry to the touch. Finally, use a strip of velcro to rough out the thorax and create legs. If you like, gently flatten the abdomen with a pair of needle-nosed pliers to more closely imitate the natural.

Here in the Northeast anyway, an iso nymph fished with a good bit of movement will catch trout pretty much year round. Tie a bunch as these are easily lost to the bottom.