Fly Identification Guide

Narrow it down

Nearly every trout fly belongs to one of five groups. Two questions get you most of the way there. Does it float, and what is it shaped like.

1. It floats, and it is foam, rubber legged or chunky. Terrestrial. Something that lives on land and fell in.
2. It floats, and it has a hackle collar, an upright wing or a hair wing. Dry fly. An adult aquatic insect on the surface.
3. It sinks, it is slim, and it has a bead at the head. Nymph. An immature insect drifting below the surface.
4. It sinks, it is long, and it has marabou, flash or a rabbit strip. Streamer. A baitfish, leech or crayfish.
5. It sits low in the film, with a soft hackle or a trailing shuck. Emerger. An insect caught halfway between nymph and adult.

If it does not fit any of those, it is most likely a traditional wet fly, covered further down.

The five groups at a glance

Dry flies

A dry fly imitates an adult aquatic insect sitting on the surface. It floats on hackle fibres, stiff hair, CDC or foam, and it is the only category where you watch the fish eat.

Fish it when you can see rises, or during a known hatch. A trout rising steadily in one spot is eating something on or just under the surface, and a dry is the first thing to try.

Common patterns. Parachute Adams, Elk Hair Caddis, Blue Winged Olive, Griffith's Gnat, Royal Wulff.

Season. Spring through autumn, concentrated around hatch windows. Blue Winged Olives run cool and grey days in spring and autumn. Caddis run warm summer evenings.

Nymphs

A nymph imitates an aquatic insect in its immature stage, before it ever reaches the surface. Most of what a trout eats over a season is subsurface, which is why nymphs catch more fish than every other category combined.

How to spot one. Slim, drab, usually a brass or tungsten bead at the head to get it down. Some carry a wire rib or a flashback.

Fish it when nothing is rising, which is most of the time. Dead drift it near the bottom, under an indicator or on a tight line.

Common patterns. Pheasant Tail, Hare's Ear, Copper John, Zebra Midge, Prince Nymph.

Season. All year. In winter it is often the only thing worth tying on.

Emergers

An emerger is the stage between nymph and adult, hanging in or just under the surface film while the insect works its way out of its shuck. It is the most vulnerable moment in an insect's life and trout know it.

How to spot one. Sits low rather than perched up. Look for a trailing shuck, a soft hackle, a wing bud, or a body that hangs below a small float point.

Fish it when fish are rising during a hatch and refusing your dry. That refusal usually means they are taking emergers an inch under the surface, not adults on it.

Common patterns. RS2, Klinkhamer, soft hackle, Barr's Emerger.

Season. Whenever there is a hatch, so spring through autumn.

Streamers

A streamer imitates something that swims rather than drifts. Baitfish, sculpins, leeches and crayfish. You retrieve or swing it, and the take is usually a hard grab rather than a subtle sip.

How to spot one. Much larger than the rest. Marabou, flash, rabbit strip or a jig head. Often articulated into two hinged sections.

Fish it when the water is high or off colour, in low light, or when you would rather look for one big fish than catch several small ones.

Common patterns. Woolly Bugger, Clouser Minnow, sculpin patterns, articulated streamers.

Season. Strongest in spring high water and autumn before spawning, but a Woolly Bugger works any month of the year.

Tie a streamer on with a loop knot rather than a clinch so it can swing freely. The fly fishing knots guide covers the non-slip loop.

Terrestrials

A terrestrial imitates an insect that lives on land and ended up in the water by accident. Grasshoppers, ants, beetles, crickets and cicadas.

How to spot one. Foam bodies, rubber legs, bright indicator posts. Chunkier and less delicate than a dry fly.

Fish it when it is mid to late summer, especially on a windy afternoon along a grassy or undercut bank. Wind puts land insects on the water.

Common patterns. Chubby Chernobyl, foam ant, Dave's Hopper, foam beetle.

Season. July through September in most trout country. Ants can work any warm month.

Wet flies

The oldest category, and the one people forget. A traditional wet fly is a soft, sparse pattern fished under the surface on a swing rather than a dead drift. Soft hackle patterns like a Partridge and Orange are the surviving examples.

They predate modern nymphing and still work, particularly during a caddis hatch when fish are chasing rising pupae. Sizes 10 to 16, fished on a tight line across and down.

Matching tippet to the fly

The quick method is the rule of three. Divide the hook size by three and you get a workable X rating. A size 18 fly wants roughly 6X. A size 12 wants roughly 4X.

The rule stops being useful above about size 8, where most anglers move to 0X through 3X or to straight pound test. That is why the streamer row in the table above does not follow it.

Two tools do this properly. The fly size to tippet matcher gives the balanced range for any hook size from 2 to 28, and the tippet size calculator converts an X rating into diameter and breaking strength.

Working out what is hatching

Identifying the fly in your box is half the problem. The other half is knowing what the fish are actually eating today, which changes by month and by water temperature.

The fly fishing hatch chart covers the major mayfly, caddis, stonefly and terrestrial windows through the season. The trout water temperature guide covers when fish will feed at all.