Behind Fly Patterns

Decoding some fly-fishing terminology

Over the past couple of decades, dry fly fishing, in particular, has spiked in popularity. There’s something magical about casting a dry fly and the sheer beauty in the curve of a fly line as it cuts through the air, arching towards its target. It’s almost a religion to some people! My guess is that the Hollywood movie A River Runs Through It sparked a lot of this hype. However, for newbie fly anglers, there’s no question that fly fishing is complicated and features a vocabulary which is a bit like a foreign language. Further, fly patterns, per se, are a dark mystery for those folks who are not acquainted with aquatic biology and entomology. What do fly patterns really mean? That’s the purpose of this article — to describe the nature of dry flies, nymphs, wet flies, attractor patterns and streamers, as well as some basic biology regarding the insects and bait fish they imitate. During public presentations I’ve made on fly fishing, it has been fairly obvious that at least some members of the audience had a vacant look on their faces when I talked about fly patterns.


Fly Fishing. Photo by iStock.
Photo by iStock.

Primary Taxonomic Orders Of Aquatic Insects

There are three major taxonomic orders of aquatic insects in either their aquatic or terrestrial stages that fish key in on when feeding: caddis flies, mayflies and stoneflies. Insects in these orders spend most of their life cycle in an aquatic stage, as juveniles, and only a short period of time in a terrestrial stage, as adults, where they mate and lay eggs in the water to complete their life cycle.

On streams, in particular, fly selection is related to the timing of insect hatches.


Stonefly hatches occur during the entire open water season, starting with snow flies after ice breakup until late summer; snow flies are small, dark stoneflies of which there are several species. It is not uncommon to see snow flies crawling on top of snowbanks on the river’s edge. Hatches of the large salmon fly and Skwala (golden stone) species occur mainly in the spring and early summer and are often of short duration. There are various fly patterns which imitate these large stoneflies, but the larval stages can also be imitated using nymphs (year-round) because salmon flies may live for two years in the larval stage. A Stimulator with an orange abdomen imitates a larval salmon fly. An El Camino is a good dry fly imitation of an adult golden stone.

Caddis flies emerge during the open water season from the spring until the autumn when a particularly large species, the October Caddis, can sometimes be seen flying awkwardly over the water. These large caddis flies are targeted by trout. A Stimulator with dark abdomen is a good imitation of them. During the summer, an Elk Hair Caddis has long been a go-to fly pattern.


Mayflies tend to hatch primarily during the summer and only survive for about 24 hours as adults. There are dozens of mayfly species in British Columbia. Brown and Green Drakes, a Parachute Adams and the Royal Wulff are popular patterns that imitate mayflies.

You can never have too many attractor patterns.
You can never have too many attractor patterns.

Go-To Dry Flies: Match The Hatch

Keen fly fishers have dozens of dry flies to “match the hatch,” which is jargon for using fly patterns that mimic whatever insects might be hatching. Flies come in numbered sizes: small numbers represent large hooks and large numbers represent small hooks. A #24 fly is so small it’s hard to see and even harder to tie onto a tippet without the aid of a magnifying glass; it’s very hard to spot this size of fly on the water. There’s no universal rule that dictates the appropriate size of a fly when fly fishing, it all depends on the circumstances. If there’s an insect hatch, it’s best to match the hatch with an appropriate fly pattern and size. However, under some circumstances, going a size or two larger doesn’t hurt and may lead to more rises. On heavily fished waters, trout can become shy of large flies so it’s often better to use size #14 to #16 or smaller flies. Hatches tend to be highly synchronized events. Often, there are few bugs in the air, especially during the day, because major insect hatches occur during the evening when winds tend to be calm. 

Attractor Patterns

If there’s little sign of a hatch in progress, it’s best to use attractor (search) patterns, large gaudy flies such as a Big Ugly, Turks Tarantula, Madame X, Chernobyl Ant, Stimulators and Water Walkers that imitate adult stoneflies, or Hopper patterns which imitate grasshoppers. Granted, if you see adult caddis flies, mayflies or stoneflies aloft, you should search your fly box for an imitation. But what do you do if there are no airborne insects? First off, start with an attractor pattern and cast the fly over promising holding water. These flies don’t imitate anything in particular, but they do resemble a lot of different insects, some aquatic, some terrestrial, and are great to get a rise from active fish. Also, watch for actively feeding, rising fish and try to figure out what they’re taking as you work the water. Often, they’ll be feeding on small mayflies or stoneflies during the morning, which can be difficult to see. Most of the time you’ll find a decent attractor pattern that will be a producer, but you may have to experiment with several patterns before finding the right one. On waters that see a lot of angling pressure, try new or unusual patterns, larger or smaller than usual sizes of flies, something out of the ordinary that other fly anglers are not likely to be using. Many fishing guides will resort to large Green Drakes or Water Walkers when the customary attractor patterns don’t produce.

On streams, fly anglers must also think seasonally. For example, what kind of insects are fish likely to be feeding on at that time of the year. Think outside of the box because in late summer and during the autumn, terrestrial patterns like ants, beetles and grasshoppers are often your best bet. A Fat Albert is a good hopper imitation, as are the Frankenhopper, Letort and Mo Joe hoppers. Are you starting to get the picture? If you don’t have your bases covered with ants, beetles and hoppers, you may go home skunked.

On lakes, you might notice fish rising but no insects in the air. Usually, this is a sign that they’re taking bugs on the lake’s surface that are emerging during metamorphosis from their larval stage to adults. This is when you need an emerger pattern, not a dry fly but one that sinks partly in the surface water, such as a Klinkhammer. Another tip when fly angling on lakes is to look for midge “shucks” (i.e., larval exoskeletons) on the surface of the water. Focus your fly fishing in areas underneath these spots with a chironomid pattern because trout and grayling will often lurk nearby.

Bull trout can be taken with Cone Head Woolly Buggers.
Bull trout can be taken with Cone Head Woolly Buggers.

Nymphs, Streamers & Wet Flies

If trout aren’t taking dry flies, you might want to switch to a nymph, streamer or wet fly. Just because fish aren’t rising doesn’t mean they’re not feeding; they tend to feed on aquatic invertebrates drifting in the current of freestone rivers and tailwater streams all day long. During the summer, most fishing guides will recommend a hopper-dropper rig during the heat of the day on streams to hedge their bets – a grasshopper pattern with a nymph tied onto the hopper to catch the interest of fish feeding on top and underwater. Some go-to nymphs I’d recommend are the Copper John, Pheasant Tail and Prince Nymph in addition to the Hare’s Ear and San Juan Worm which are old standbys.

A variety of colourful streamers will take lake trout.
A variety of colourful streamers will take lake trout.

You don’t need a host of different nymphs when fly fishing still waters. Bead Head Chironomid (midge) patterns are always a good choice, although various bead-head nymphs (i.e., Bead-head Prince, Pheasant Tail and Hare’s Ear nymphs) are all close seconds. There are several searching nymphs, for example dark halfbacks, that are also producers – which would normally be fished without a strike indicator, but rather by casting into promising lairs and retrieving them with short strips.

The $64,000 question is always where do you actually go fishing on still waters? The littoral area along the shoreline is generally your best bet, especially in bays, channels between islands, along points that jut into the lake, near underwater structures such as boulders and sunken logs where trout and char can find some sanctuary. When in doubt, look for insect hatches to narrow your search, because trout will never be far away. Pupal cases (i.e., insect shucks) on the water’s surface are a good sign of recent hatches, as well as swallows flying low over the water. Insect hatches on still waters can occur at any time during the day, but they are most common in the evening when winds are calm.

Be prepared to switch to nymphs, streamers and wet flies if dry flies don't work.
Be prepared to switch to nymphs, streamers and wet flies if dry flies don’t work.

For streamers, stock up on the Autumn Splendor, Bow River Buggers, Gartside Leech and earth-coloured Zonkers. The Woolly Bugger is a popular streamer that comes in many different styles and is one of the better streamers, black, olive or brown in colour. There have been numerous changes made to the Woolly Bugger fly pattern since it was first introduced; for example, some are fashioned with cone heads, the shank may or may not be weighted, while some come with rubber legs. You’ll find it’s often necessary to change colours when using streamers to get regular hook ups. The Egg Sucking Leech is another popular streamer. A Marabou Leech pattern is yet another go-to streamer, and a consistent producer. The Mickey Finn and Muddler Minnow patterns have long been go-to streamers, especially in flowing water. The Muddler Minnow can be deadly on bull trout. Deceivers are excellent streamers for lake trout, in particular, as well as northern pike. In still waters, try a Hornberg Special streamer, which can be dynamite on cutthroat, rainbow and brook trout in lakes and also beaver ponds. It can be awkward to cast large streamers, and in particular those made of natural dressing. For these reasons, I’d suggest using streamers made of synthetic material instead of natural fibres, unless you’re going to troll them.

Deceivers, Cone Head Woolly Buggers and Zonkers are all good fly patterns for lake trout.
Deceivers, Cone Head Woolly Buggers and Zonkers are all good fly patterns for lake trout.

Wet flies don’t seem to be in vogue in fly fishing circles nowadays. These traditional flies are great for catching grayling, trout and mountain whitefish. Some of the more popular, traditional wet fly patterns are the Adams, Black Gnat, Brown Hackle, Doc Spratley, Grizzly King, Light Cahill and Royal Coachman. Wet flies can be fished with or without a strike indicator, the same for nymphs, it’s all a matter of personal preferences.

Beware of generalizations respecting the choice of fly patterns. To use some clichés, “Don’t put all your eggs in one basket” when fly angling and be ready to “throw everything at ‘em” during the seasons when you’re on the water.