I was making my weekly rounds through The Patient Angler Fly Shop earlier today and got on the topic of flies for the Crooked River. Peter, the shop proprietor, shared a recent experience:
He pulled up to his favorite hole, only to find it crowded with a group of anglers. Peter patiently waited as the group eventually packed up and headed back to their cars.
“Did you catch anything?” he asked.
“Nope,” they said. “There aren’t any fish in this run.”
Peter made his way down… and proceeded to pull 10 fish out of that very hole.
The difference? Tiny bugs.
Bigger Isn’t Always Better
There are plenty of reasons anglers reach for big bugs. Maybe they see caddis hatching and grab the first one they see in their fly box—laziness. Maybe they believe that bigger flies catch bigger fish. Or maybe they think a larger fly is just easier for a trout to see.
Sometimes, it’s a simple case of misjudging size. A skittering caddis looks a lot bigger on the water than it does resting on a leaf near the bank.
Matching the hatch doesn’t just mean using a dry fly labeled “mayfly.” There are dozens of different species of mayflies in any given stream. Some are big—like Hexagenia—while others, like tiny BWOs, are barely visible to the naked eye. With such a wide range of bug sizes, we need to look more carefully at what trout are actually eating.
Why Small Flies Work Better (Most of the Time)
My buddy Lucas and I were talking one morning about using large vs. small stonefly nymphs on a local river. The conversation drifted into insect lifecycles—and how much their size varies throughout the year.
A stonefly nymph doesn’t just become that big overnight. It grows over time. And since they can take multiple years to mature, there are multiple generations of nymphs in the water at any given time, each at a different stage. The adult bugs we see crawling along the rocks? They’re the survivors—the minority, not the majority.
This is one reason I lean toward smaller flies, especially on pressured rivers. Most anglers throw huge stoneflies because they’ve seen adult salmonflies on the banks and assume that’s what fish want. But I’d rather tie on a smaller, more immature stonefly to imitate the broader biomass of nymphs drifting below the surface.
In general, there are simply more small bugs in the river. Not every insect makes it to maturity—far from it. The ratio of eggs laid to adult emergence is massive. So while adult insects may look uniform in size, the subaquatic buffet trout feed on is made up of countless smaller stages.
Your size 12 or 14 stonefly likely looks more natural drifting through a riffle in October than a size 6 salmonfly. (Remember: salmonflies hatch in May on the Deschutes.) A smaller fly draws less suspicion, especially in clear water.
Matching the Natural Forage
As fly anglers, we should always aim to imitate what the fish are actually eating—not just what’s easiest for us to tie on.
Many rivers in Oregon (and beyond) are loaded with midges, micro-mayflies, and other tiny aquatic insects. It may not be as fun to tie on a size 22 midge, but doing so will often produce better results.
When Peter was on the Crooked River, he noticed the trout were nosing up just below the surface—not quite rising. They were feeding on emergers. Using his decades of local knowledge, he tied on a size 22 emerging midge and absolutely cleaned up, fishing the same water where the previous group got skunked.
How to Fish Small Flies Effectively
1. Use lighter tippet.
Yes, thinner tippet can be harder to fight fish on—but if you’re playing fish properly, 5x to 6x will hold. Thicker tippet has two major downsides when fishing small flies:
- It’s harder to thread through tiny hook eyes.
- It reduces the natural drift due to increased stiffness.
2. Fish longer leaders.
Small flies tend to shine in softer currents with swirling micro-eddies. A long leader gives your fly the slack it needs for a true drag-free drift and helps you stay stealthy in tight seams and backwater pockets.
A Final Tip on Fly Size
A guide once told me:
“Pick the fly that matches the hatch, then go one size smaller.”
It’s a simple rule, but one I follow constantly. When I compare a drifting spinner or caddis on my hand to my fly box, I always go one size down. That small change often makes the difference between fooling a wary trout and going home empty-handed.
And don’t worry about whether fish can see your fly—they can.
Fish spend their entire lives watching food drift toward them. Between their visual acuity and their lateral line sensitivity, they’ll find that size 22 midge long before you even spot your own indicator.
Fish On, and Fish Small.
—T
Leave a comment