A trout decides to eat your hopper before it gets a good look at it. The first thing that reaches the fish isn’t the color or the hook size — it’s the sound and the pressure wave of a big insect hitting the water. By the time the fish can see the fly clearly, it’s already moving to eat or it’s already gone. So worry less about what’s in your fly box and more about how the fly lands. You’ll catch more fish in August that way than you ever will by swapping patterns.

That’s not a license to fish sloppily or to carry one fly. Color and size do matter in certain water and for certain fish — the slow, clear, hard-fished places especially. But for most hopper fishing on most rivers, here’s what counts, in rough order: a drag-free drift, the way the fly lands, where you put it, how it sits on the water, and last of all the fly itself. Get the early ones right and it usually won’t matter much which hopper you tied on.