How to use your Hatch Theory box

You have the box. Each of the six named patterns inside has its own section below, with what it imitates, when to tie it on, how to fish it, and what a take looks like. Read straight through before your first trip, or pull this up on the bank when you are deciding what to try next.

Before you fish

A 9-foot, 5-weight rod will handle every pattern in your box, paired with a floating fly line, a 9-foot tapered leader, and spools of 4X and 5X tippet to cover the size range. You will also want nippers, hemostats, polarized sunglasses, floatant for the dry flies, and a few small split shot for the nymphs. Tie your fly to the end of the tippet with a clinch knot, and if a nymph is not getting deep enough, pinch a split shot onto the tippet about a foot above the fly. The other questions (which fly, when to switch, how to read the water) are what the rest of this article is for.

The surface flies

These three patterns imitate the adult, winged stage of an aquatic insect or a terrestrial that has fallen in. A trout eating one creates a visible ring or splash on the water.

Parachute Adams

What it imitates. An adult mayfly. The neutral grey body and white post are close enough to dozens of species that trout treat the fly as "mayfly" without checking.

When to tie it on. When you see small bugs in the air and fish making delicate ring-shaped rises. Most days from late April through October will have at least one such window, and a size 14 is a safe first guess when you cannot identify the bug.

How to fish it. Cast upstream of a rising fish or a likely lie (the seam between fast and slow water, behind a rock, along a current line) and let the fly drift back at the speed of the water around it. If the leader is pulling the fly faster than the surrounding bubbles, mend with a small upstream flick of the rod tip.

What a take looks like. A clean ring around the fly, sometimes a small splash, then the fly disappears. Wait a half-second so the fish has time to close its mouth and turn, then lift the rod tip smoothly. A calm lift sets the hook.

Elk Hair Caddis

What it imitates. An adult caddisfly. Caddis sit differently than mayflies, with wings folded into a tent shape and a body that twitches instead of drifts, and the Elk Hair Caddis copies that silhouette.

When to tie it on. In broken, fast riffles, or in the evening when fish hit the surface with a splash instead of a quiet sip. Caddis hatches run all season but are heaviest from May into August.

How to fish it. Default is a dead drift, same as the Parachute Adams. The variation trout sometimes prefer is a small twitch every few seconds so the fly skitters an inch or two, since real caddis flutter and a motionless fly during a caddis hatch can get ignored.

What a take looks like. A splash you usually see before you feel anything on the rod. Caddis-eating trout are aggressive, so set with a calm lift, not a jerk.

Stimulator, orange

What it imitates. A larger, brighter attractor pattern that does not copy one specific insect but suggests a stonefly, a big caddis, or any meaty meal floating by. The bright body and high-floating wing make it easy for you to track and easy for a trout to commit to.

When to tie it on. When the water is rough and broken, the kind where a small Adams disappears in the foam before you can track it. Also when you are searching unfamiliar water with no rising fish visible and the question is whether anyone is home.

How to fish it. Dead drift through likely holding water. The Stimulator floats high enough to act as the top of a dry-dropper rig: tie 18 inches of tippet off the bend of the hook, attach a nymph to the other end, and the dry becomes your strike indicator.

What a take looks like. A solid, committed eat. Stimulator fish are usually not picky, so set the hook a half-second after the take.

The subsurface flies

Most of a trout's life is spent eating things that never reach the surface. The next two patterns are nymphs, imitating the larval stage of common stream insects as they drift along the bottom where trout do most of their feeding.

Pheasant Tail Nymph

What it imitates. An immature mayfly, slim and segmented with a brown-bronze body. Mayfly nymphs cling to rocks on the streambed and drift downstream when current dislodges them or when they are about to hatch.

When to tie it on. When no fish are rising, when the water is cold, or any time you want a slim natural profile rather than a flashy or buggy one. Early in the day, before any hatch has started, is a classic window.

How to fish it. Below a strike indicator (a small foam or yarn marker pinched onto your leader four to six feet above the fly), or below a buoyant dry like the Stimulator. Cast upstream so the fly has time to sink, then watch the indicator drift back. The indicator is your eyes, since you cannot see the fly.

What a take looks like. You will rarely see the fish. You will see the indicator do something the current cannot explain (a pause, a sudden plunge, a hard sideways pull), and you set on anything the river itself cannot account for.

Hare's Ear

What it imitates. A generalist subsurface fly. The buggy, scruffy profile and tan-brown colour can pass for a caddis pupa, a scud, a sowbug, a small stonefly nymph, or simply organic matter that looks alive enough to eat.

When to tie it on. When the Pheasant Tail has not produced, when the water is dirty or off-colour, or when you do not know what is in the river and want a pattern that covers the most options at once.

How to fish it. Same setup as the Pheasant Tail (indicator above, dead drift through likely holding water), with the difference that the Hare's Ear sinks a little faster because of its denser body, so you may not need split shot to get it down.

What a take looks like. Same as the Pheasant Tail. The indicator pauses, plunges, or pulls sideways, and you set on anything the river cannot account for.

The swimming fly

The last pattern is not a drifting insect. It moves through the water under its own power, and you supply the motion. Streamers cover water quickly, search for bigger fish, and work when the river gives you no other information.

Olive Woolly Bugger

What it imitates. A baitfish that trout chase for a real meal, or a leech undulating along the bottom of a slow river or lake. The marabou tail moves on its own in the slightest current, which is what makes the fly look alive.

When to tie it on. When the water is high, dirty, or cold and the bugs are not active. Also when you are covering a long stretch quickly, or when nothing else has produced and you want to find out whether anyone is willing to chase.

How to fish it. Cast across the current and slightly downstream, then let the fly swing across on a tight line, the way a baitfish would be pulled by the flow. Give the line occasional small strips so the fly pulses, and at the end of the swing pause for a few seconds before recasting, because a lot of fish hit on the pause.

What a take looks like. A thump on the rod, or a hard jolt, or a steady weight that was not there before. The fish has already turned with the fly, so you do not need to set hard.

The seventh slot

The box has one more pattern, which we have not named on this site or anywhere on the packaging. You will see it when you open the box and recognize it for what it is. When the moment to tie it on arrives, a specific kind of day on a specific kind of water, you will know that too.

Your first day

Pick the category before the fly. Surface if fish are rising, subsurface if the surface is quiet, streamer if you cannot read either. Give each fly fifteen good drifts before changing, because the river is not always wrong about your pattern (sometimes it is wrong about your position). Tie a fly on, deliver it into water a trout could have eaten it from, and read what happened next.