tying

Put Your Fly Patterns on a Diet

By Jeff Morgan

Many fly patterns are simply too fat. Here's some tips for keeping your flies skinny and naturaly looking.

hether they're tied in Bangladesh or in your basement, many fly patterns have a basic problem: obesity.

Real insects are immune to the perils of over-indulging in Whoppers and ice cream, and patterns that match their actual body proportions will outperform "fat" patterns on today's heavily fished trout streams.

Next time you're on the water, collect some bugs and compare them to your flies. Regardless of how exactly imitative your flies are, they will likely turn out to be both thicker and longer than the natural insects. Most anglers can buy or tie smaller flies, as they only need smaller hooks. However, controlling the thickness of patterns requires special attention.

Profile, Movement, and Money

Thickness causes more problems as fly sizes shrink. If a size 12 nymph is 1mm too thick, very few trout will take offense. If, however, a size 20 nymph is 1mm too thick, it will make the girth 50% to 100% larger than the natural insect. Most trout will notice the difference--and you'll notice that you're not catching many trout.

Besides giving your fly a more natural profile, a thinner fly usually moves better underwater. And it saves you money because you'll almost half the material that you normally would.

However, not all flies benefit from slimming down. Dragonfly nymph patterns should be bulky, as these insects have all the nose-to-tail taper of a wild turkey. Baitfish patterns, such as sculpin imitations, should have considerable heft to them. Even some mayfly nymphs, such as green drakes, should be built as short and stout as an Olympic gymnast.

With those exceptions in mind, let's examine three commonly used imitations that greatly benefit from the fly-tying equivalent of a Jenny Craig program: leeches, midges, and small mayfly nymphs.

Leeches

If you watch a real leech swim you'll notice that it looks long and skinny as it wriggles and thrashes through the water. It does this to maximize its surface area, which makes its swimming motion more efficient. But when you capture a leech and it sits on your hand, it appears thick and flat. Unfortunately, most of our patterns imitate the appearance of the static leech.

The most common commercially tied leech imitations--Woolly Buggers, Bunny Leeches, and Mohair Leeches--are bulky and generate a broad silhouette, even when wet. All this bulk doesn't allow the fly to move and breathe underwater, and the fly looks dead, a wax statue of the natural food.

A pattern like the Slim Fast Leech, which is simply a sparse Woolly Bugger with woolly chenille, looks much more like a leech than the same pattern tied with standard chenille and a thick clump of marabou. The same short strips that simply cause the thick pattern to change direction, cause a skinny pattern like this one to dance, breath, and move like the natural.

Chironomids

Most stillwater anglers can fool at least a few trout most any day of the season if they imitate a chironomid (midge). Chironomids are so abundant that many anglers are lulled into complacency with their tying. As these insects emerge in calm water, the trout have a long time to inspect them. If you are fishing thick imitations, those inspections more often than not turn into rejections.

Color and length are important and receive well-deserved attention from fly tiers. But diameter is just as important. Skinny patterns catch more fish than thicker ones.

A natural chironomid is rarely more than 1/10 as thick as it is long, which is usually just a shade thicker than the hook on which the pattern is constructed. To keep chironomids thin, use thread, Krystalflash, mylar tinsel, or tautly pulled Flexifloss for the body. Avoid dubbing and Larva Lace type materials, as they can easily blow your pattern up to a Marlon Brando-esque girth.

A thin body doesn't require you to tie plain jane imitations. The Bloody C's silver mylar tinsel under body, red Flashabou rib, black/red thorax, bead, and CDC tuft at the head creates a complex-looking pattern without blimping up the overall silhouette. A slight brushing out of the thorax gives a softer look to the fly underwater.

Mayfly Nymphs

Mayflies have a diversity of shapes during their nymph stage. Some of the strong clingers (March browns, yellow quills, etc) have a thick thorax and stout legs. These mayflies are the ones that most of our thick-thoraxed and legged imitations (Hares Ears, Pheasant Tails, Skip Nymph) are designed to match. Unfortunately, these insects are such strong clingers, that they are rarely fed upon by trout.

The three mayfly nymphs most heavily preyed on by Western trout--Baetis, Callibaetis, and PMD--all have a skinny, slim profile with diminutive, skinny legs more apt for positioning themselves on vegetation than clinging to rocks in whitewater.

The silhouette of these mayflies is surprisingly thin, and there is almost no difference between the diameter of the thorax and the abdomen.

For these mayflies, constructing a skinny nymph like the CDC PMD Nymph is a good alternative to the bloated thoraxes on standard patterns. Notice the lack of legs, gills, or excessively picked out thorax. These additions are for the eyes of anglers, not fish. They can greatly reduce the effectiveness of your patterns.

In addition to keeping the slim profile of the natural mayfly, this pattern has a CDC wingcase, which gives you the option of fishing the fly in the film or deep under an indicator. The old standard, the "floating nymph" with a ball of dubbing and parachute hackle, can only be fished in the surface film.

By changing the color and size, you can effectively imitate several different kinds of mayflies with this pattern.

Five Easy ways to Watch Your Fly's Waistline

1. Avoid chenille and yarns for bodies of small flies. These add useless bulk and you'll have more control with dubbing. The exception to this is patterns larger than size 10, where dubbing is less practical.

2. Trim materials at the tie-in point: If you tie the materials down, there is a larger base to build over materials

3. Minimize thread wraps: fewer wraps mean less bulk at tie in points

4. Use a thinner thread: 8/0 should be standard fare for most patterns, and for small dries and nymphs, 14/0 "midge" thread is more than enough for most applications.

5. Dub tighter. Whether you dub directly to the thread or make a loop, making your dubbing tighter will allow you to keep your fly slim and create more realistic tapers.

Jeff Morgan has written many articles for Westfly, mostly on entomology and fly tying. He is the author of An Angler's Guide to the Oregon Cascades and Small Stream Fly Fishing. Jeff is currently a graduate student at Stanford University, where he is finishing his PhD in History.

Uploaded 07/09/2002.

Rate This Article

5=tops  3=average  1=low

You must be registered and logged-in to rate an article. How to do this.

This article has not yet been rated.

Slimfast Leech

Bloody C

CDC PMD Nymph