According to the latest fly fishing report from Orvis in conjunction with Linehan Outfitting for the Kootenai River has some “good” fishing right now.
If you’re looking for consistent action stick with nymphing. That said, dry dropper action is pretty good. #10 chubby with a #16 bead head PT will roll really well.
The best time to fish is “anytime”, and note that the Libby Dam downstream to mouth of the Fisher River is currently closed for spawning. All other stretches are fishing pretty much the same.
Here are the “Must-have” fly fishing patterns, according to Linehan Outfitting, in descending order of importance: