Dry, nymph, or streamer? A decision tree for the riverbank

Two minutes of looking at the water answers most of the question. Here is the tree that gets you to the right fly without flipping through your box for an hour.

You walk down to the river, you open your box, and the first question you ask is the wrong one. Most beginners ask "which fly?" before they have any reason to pick one. That is how you end up changing patterns six times in the first hour and never actually fishing.

The right first question is shorter. Where are the fish feeding? Once you know that, the fly almost picks itself.

This piece is a field card. It tells you what to look at, in what order, and which of the six flies in your box to start with based on what you see. Use it the way a guide would talk you through your first ten minutes on the water.

The two things to read before you tie anything on

Stand on the bank for two minutes before you do anything else. Look at the water, not the box. Two inputs decide most of it.

What the water is doing. Cold or warm. High or low. Clear or murky. You can read all three in a glance. Cold and high and murky points one direction. Warm and low and clear points the other.

What you can see. Are fish breaking the surface? Are there bugs in the air? Are bugs landing on the water near you? Is there a fish you can actually spot, or are you guessing? Each of these signals points to a different fly.

These two inputs are the whole tree. Everything below is just structure on top of them.

The decision tree

Read top to bottom. Stop at the first branch that fits what you see.

Are trout breaking the surface?
│
├── YES, and I see bugs in the air or on the water
│   │
│   ├── Bugs are upright and delicate (mayflies)
│   │   → Parachute Adams (size 14)
│   │
│   ├── Bugs are tent-winged and skittering (caddis)
│   │   → Elk Hair Caddis (size 12)
│   │
│   └── Bugs are big, loud, or hard to identify;
│       or the water is fast and broken
│       → Stimulator (size 12)
│
├── YES, but I don't see what they're eating
│   → Start with the Parachute Adams.
│     If three drifts produce nothing,
│     switch to the Elk Hair Caddis.
│
└── NO surface activity
    │
    ├── Water is cold, high, or murky;
    │   or you cannot see a fish to target
    │   → Olive Woolly Bugger (size 8)
    │
    └── Water is normal, fish are likely
        feeding on the bottom
        │
        ├── Clear, slow-to-medium water
        │   → Pheasant Tail Nymph (size 16)
        │
        └── Mixed or unknown conditions;
            "I don't know what to try"
            → Hare's Ear (size 14)

That is the tree. Six leaves, six flies. Every fly in your box has a job and a trigger.

What each leaf is doing

A short note on why each fly sits where it sits.

Parachute Adams (size 14)

The default dry. A neutral, drab mayfly silhouette that sits high enough to see and accurate enough to fool a trout looking up. If fish are rising and you do not know what they are eating, this is the first cast. It is in the ballpark of more mayfly hatches than any other single pattern in the box.

Elk Hair Caddis (size 12)

The shape of a caddisfly is unmistakable on the water. Tent-shaped wing, skittering motion, often returning to the surface to lay eggs. If you see bugs bouncing off the water rather than drifting calmly, tie this on. It also fishes well in broken, riffled water where a low-floating fly would disappear.

Stimulator, orange (size 12)

The attractor. High-floating, bushy, visible from a long way off. Use it when the water is choppy and broken, when fish are looking up but you cannot see anything specific, or when you want a fly the trout can actually find in fast current. It will move fish that ignore a more delicate pattern.

Pheasant Tail Nymph (size 16)

A slim, sparse imitation of an immature mayfly. Use it when the water is clear and the fish are not rising. Trout do most of their feeding on nymphs along the bottom, and this pattern represents the form they see most often. Best in slow to medium currents where they get a long look.

Hare's Ear (size 14)

The generalist nymph. Buggy and fuzzy, it suggests caddis pupae, scuds, sowbugs, and anything else that drifts past a trout's nose and looks roughly alive. When you have no specific signal to work with and the surface is quiet, this is the safest bet in the box.

Olive Woolly Bugger (size 8)

The streamer. Not a drifting insect at all. Marabou tail, weighted body, fished on a swing or with a slow strip across the current. Use it when the water is cold or stained or both, when nothing else is producing, or when you want to cover water quickly and see what is willing to chase. It is the universal "when in doubt" fly.

When the tree disagrees with itself

Fishing is not tidy. The tree will sometimes give you two answers at once.

Fish are rising but the water is high and murky. Trust your eyes over the conditions. If they are rising, they are looking up. Start with a Stimulator because it is easier for them to see in stained water than a delicate mayfly pattern. If it does not produce in ten minutes, switch to the streamer.

Bugs are everywhere, but no fish are breaking the surface. Trout often eat emerging nymphs just below the surface during a hatch without ever showing themselves. Tie on a Pheasant Tail and fish it shallow, near the top of the water column.

Cold water but you can see fish holding in clear runs. The streamer is the default for cold water, but a visible, holding fish is worth a deliberate nymph drift first. Run a Hare's Ear past it. If it ignores you twice, then strip a Woolly Bugger through the same lane.

Late summer, low water, no visible activity. Hot afternoons shut down a lot of trout, but the banks can still produce on terrestrials and big attractors. The Stimulator is your starter. Walk slowly, cast tight to grass and overhanging trees, and watch for an opportunistic hit.

The pattern across these mixed signals is the same. Trust what you actually see over what the conditions suggest. The river will tell you the truth if you watch it for a few minutes longer than feels comfortable.

A note on the seventh fly

There is one more pattern in the box that is not on the tree. It is reserved for a specific kind of day. You will know it when you have it, and the box will tell you when to tie it on. Until then, the six flies above are the working answer to almost every trout day you will fish.

How to actually use this

You do not need to memorize the tree. Read it once now. Save the page or screenshot it. When you are standing on the bank, open it on your phone, look at the water for two minutes, and follow it top to bottom.

The first time, it will feel slow. By the tenth time, it will feel automatic. By the end of a season, you will not need the card anymore. You will look at the water and know, before you ever open the box, which fly is about to come out of it.

That is the whole point of carrying six instead of sixty. The box does not give you more choices to make. It gives you a small enough vocabulary that you can actually start to read what is in front of you.

The fish are already telling you what to throw. The tree just helps you listen.