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The Stoneflies

By Bill Luscombe, 🕔Mon, Mar 21st, 2011


The last of the four major aquatic insects that freshwater fish feed on is the stoneflies. Stoneflies are found only in fast moving water such as that found in the freestone streams and rivers of the northwestern United States and Canada. They are not found in lakes or slow spring creeks. Stoneflies undergo incomplete metamorphosis like the mayflies; there is no pupal stage.

In the spring the stonefly eggs hatch on the river bottom and tiny larvae appear which we commonly call nymphs. As the weeks pass the nymphs grow until their bodies become too large for their outer shell. When this occurs the outer shell (exoskeleton) splits open and the new, larger nymph emerges with a new exoskeleton. These growth stages are called larval instars. The nymphs go through many instars before emerging as adults and, depending upon the species, they can take a year or two to reach the stage where they are ready to metamorphose into the adult. This is a bonus for the fly-fisher because stonefly nymphs are available to the trout year 'round and thus are always recognised by the fish as food. Stonefly nymph patterns are good flies to use in just about any free stone stream at any time.

While the nymphs are crawling around on the bottom of the river feeding and going though their instars they are available to the trout as food and trout feed on them regularly. They often wash off the rocks to be tumbled in the current along the bottom and it is here that they offer the trout their easiest meal. A good imitation of the stonefly nymph is described below (vary the colour to match the local species):

Stonefly Nymph:

Fly Tying Instructions:


  1. Wrap the thread back to rear of hook and tie in the quill tail as you would normally for a stonefly pattern, splitting the quill to form a fork.
  2. Tie in the Larva Lace at rear underneath hook shank and leave enough excess forward to reach thorax area (about 2/3 of hook shank).
  3. Wrap the Larva Lace forward and tie off about 2/3rds of the way up the hook shank.
  4. Tie in goose quill for the wing case.
  5. Tie in the grizzly hackle by the tip.
  6. Tie in 4 strands of peacock herl.
  7. Twist them to form one strand and wrap forward to the hook eye forming a thick thorax.
  8. Tie off and trim the excess.
  9. Palmer the hackle forward through the herl.
  10. The hackle should lay back and point toward rear, about beard length.
  11. Divide the hackle fibres on top of fly to the sides, and pull the wingcase forward over the top.
  12. Tie down at the eye.
  13. Tie off and trim the excess.
  14. Whip finish and cement.

To fish the stonefly effectively you must get the fly as close to the bottom as possible. You can weight the nymph during the tying phase to help out and you can use sink-tip or full sinking lines to aid you as well. Cast up and across and follow the fly downstream with the rod tip. As the fly drifts past you lift the rod tip high to take the slack out of the line and then lower it again as the fly passes on downstream. Try to feel the fly bouncing on the bottom and watch for hesitation in the line drift. Often a rock or stick will cause the line to hesitate, but sometimes it will be a fish. Set the hook anytime the line stops moving.

The stoneflies hatch into the adults in mid-spring, usually late May - early June, but this depends upon the weather patterns for the year and the altitude of the river as well. Unlike the mayflies, caddisflies, and midges, when the stonefly nymphs are ready to hatch they don't swim to the surface, instead they crawls their way to shore and onto nearby rocks or reeds. Then they lie in the sun and split their exoskeletons open along the back. They extricate themselves from their shucks and emerge as sexually mature stonefly adults. Once their wings are dry enough the adults fly to the bushes where they finish drying their wings.

The stoneflies then mate and the females return to the water's surface to lay their eggs. When they do they make quite a disturbance on the water and this attracts a lot of attention from the fish below. Many of the insects return to the water at the same time and this is what constitutes the hatch. Since the stonefly females are very active on the water you need a very buoyant fly to imitate them well. The Stimulator is a great pattern to use during the stonefly hatch.

The Stimulator:

Fly Tying Instructions:

  1. Tie in the thread and wrap to the bend of the hook.
  2. Tie in a small bunch of elk hair. The tail should be as long as the hook gap is wide.
  3. Tie in the gold wire and the grizzly hackle tip first. The hackle should be a few sizes too short for the hook size.
  4. Form a dubbing loop and dub the body 2/3 the way up the hook.
  5. Tie off and trim excess.
  6. Wrap the gold wire forward and then palmer the grizzly hackle forward to the same point.
  7. Tie off and trim the excess.
  8. Tie in the wing. It should extend back tail length.
  9. Tie in the furnace hackle, butt first.
  10. Form a dubbing loop and dub on the orange thorax.
  11. Tie off and trim excess.
  12. Palmer the hackle over the thorax so some of the orange is exposed.
  13. Tie off and trim excess.
  14. Whip finish and cement.

Most of the instruction you receive, directly or through magazines, videos, etc., tells you to present the fly to the water in a nice delicate soft landing. The stonefly hatch breaks this rule. The stonefly females very often land on the water with a small splash and to fish the stonefly hatch effectively you should do the same with your imitation. Aim your delivery a bit low so that when the fly lands on the water it splats down. This is called the splat cast. Under most circumstances this type of violent delivery will spook the fish nearby. When the stoneflies are hatching though the trout are keyed into this splashy landing and know that it means dinner is served.

If you don't get a strike immediately, allow the fly to drift drag-free downstream a bit and then make it skitter and dance a bit on the surface. The stoneflies move about actively on the surface and this can attract a trout's attention as well. Because the stoneflies move and dance about so much on the water the trout slash and swipe at them. Keep this in mind when you fish this hatch because the strikes are often violent.

Stoneflies offer some very exciting fishing on our freestone streams. Check your local waters to note the size, shape, and colour of the naturals, then tie some imitations up and give them a try. It's a great hatch.

Bill Luscombe has been hunting and fishing for most of his 42 years. He has been flyfishing for 20 years. He instructs flyfishing, and has done so for the past 12 years. He also instructs the federal FSET firearms course and the BC CORE hunter training course. He is an award-winning outdoor writer and has been writing freelance since 1987. He has been published in BC Sport Fishing Magazine, Outdoor Edge, BC Outdoors, Western Sportsman, Island Fish Finder, and the BC Hunting Guide.

Bill Luscombe was born an army brat and raised in Ladner (Delta, BC) where he was raised hunting waterfowl and pheasants. He presently resides in North Cowichan on southern Vancouver Island where he has lived and worked full time as a professional forester since 1982.

He presently works in Nanaimo for the BC Forest Service and continue to write the fly-fishing column for BC Sport Fishing Magazine as well as contributing articles freelance to various outdoor magazines in western Canada. Bill Luscombe is also a BC Director of the Northwest Outdoor Writers Association.

"Catching fish is not hard. You simply need to understand what makes them tick. If you think like a fish, you will catch fish. It´s as simple as that."- Bill Luscombe



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