I relined my fly pole and went to a lake to try to catch trout.  Choosing a fly you are supposed to match what you see flying around but what if everything flying around is smaller than every fly you have?  Is there a fly that is good anytime?

Please try reading this it will teach you a lot about  insects and fly fishing .  90% of the time the trout eat under the surface .

click on this link Fly Fishing 101 insects are there but the rest is worth a look at too.

Like rod tosser said trout eat mostly under the surface. try turning over a few rocks and see if you can figure out whats crawling around. there is probably an abundance of Chromanids, scuds and possibly damsel or dragonfly nyphs swimming around. another good bet may be a streamer that imitates bait fish. The link that rod tosser posted is a good one. I refer to that website often.

Brian

Also, try using an attractor pattern like a Royal Wulff or a Chernobyl Ant, which act sort of like a bright-colored lure for bass in that they don't imitate anything specific, but as a reaction to something foreign, fish usually push it around a little or eat it if they're feeling aggressive.

I have been looking at that website a lot lately it is very helpful.

Forget what you see flying around, turn over some rocks and observe what you see.  They're probably feeding on macro invertibrates

I would usually use an attractor like an orange kauffman's stimulator or a nymph like a pheasant tail nymph.

you will catch more Trout using a nymph or streamer than you will with Drys!!! it's a fact they eat more underwater creatures than things on the surface!!!