There are streams in and around the Yellowstone area where the fish
will hit hoppers and ants, but not the usual arsenal of dry flies. In
many cases, the "hopper season" kicks in around July 20 or so. I have
floated many different dry fly patterns (wulff's, caddis, drakes, BWO,
so forth) over the same hole, only to have zero hits except for an
occasional small trout that was more curious than determined. I then
would tie on a well defined hopper pattern (usually a long skinny
hopper , with a small white parachute at the head), only to have 14-16
inch rainbows rush off then bottom to take the hopper. They definitely
key on them, and not only will you get more fish, but many times the
hoppers will bring the larger fish right up from the bottom of the
deepest pools and runs.

I was fishing a stream a year or so ago just north of Yellowstone on a
Montana national forest. I had approached a wide bend in the river,
amid some good sized cliffs with pines and cottonwoods scattered in
lovely tall grass meadows. It was one of the deeper pools on the river.
At the head of the pool, a large old log sticks just barely out of the
water. Just beyond it is the deeper water. I made many casts with some
caddis, BWO's, wulff's, humpy's, stimulators, drakes, you name it. Not
a fish took, and this was about as "good fish" water as you are going
to find anywhere. I tied on a very detailed hopper pattern and made a
nice cast to just beyond that log. Immediately, a 22-24 inch rainbow
leaped out ofthe water, with my hopper in it's mouth. It had a belly
like a bison, and slapped down into the water like a big fat beaver. I
set the hook, and within seconds the rod was doubled over and I had
gone to my backing as the fish ran downstream. It then broke off.


Hoppers are good.

I find they work much better out in the northern rockies where they
actually have trout in the streams.