Insects and other foods the trout may be eating:
1.   Blue-winged Olives - mostly Little BWO - Isolated hatches
2.   Cinnamon Caddis - Mostly Abrams Creek
3    Light Cahills - hatching
4.   Midges - hatching in isolated locations
5.   Little Short-horned Sedges - should hatch randomly for 2-3 months
6.   Streamers - matching sculpin, baitfish and small crawfish
7.   Little Yellow Stoneflies - hatching
8. Green Sedges - hatching
9. Little Sister Caddisflies - Mostly Abrams Creek
10. Eastern Pale Evening Duns - (called Sulfurs by some)
11. Sulphurs - hatching in isolated areas
12. Golden Stonefly - hatching
13. Little Green Stonefly - hatching
14. Slate Drakes - hatching
15. Beetles
16. Grasshoppers

The Learning Process - Part 4
The first year Angie and I went to Yellowstone, we fished in and out of the park for
forty-five days. About half of those days were spent inside Yellowstone National
Park and the other half visiting streams near the park. I always keep a written log in
a notebook of what we do each day when we are fishing. We also record most
everything things on video and later log everything in yet another log book.

The first day we arrived at Yellowstone, we checked in our room at West
Yellowstone and went inside the park late that afternoon to fish. The Firehole has
its own built in heating system called geysers. The added warm water turns the trout
in the Firehole River on long before those in the other streams but about the end of
June, the water usually get too warm and the fishing action slows down. The
water in the Firehole was already too warm for good fishing in most sections of the
river when we arrived, we just didn't know it. There were only a few anglers along
the river when drove up the stream. We meet a man in the parking lot putting his
waders up who told us that he had caught about a dozen trout on a small dark
brown, almost balck ant according to my log. The guy proceeded to give us one of
his ant flies.

We walked down to the stream to the same area he had fished and I caught a 12
inch brown trout before Angie got the camera setup. A few minutes later I caught
another smaller brown trout and then I lost the little fly. I searched through our
boxes of ants but could not find one close to the one he gave us. All of our ants
were far to large compared to the one he gave us which was about a size 20. I
changed flies until dark and never got another take.

The next morning at Bud and Lilly's Fly Shop, I purchased the closest thing I could
find to it. That following day we returned to the park from fishing the Madison
outside the park about two hours earlier than the day before. It was quite obvious
then in the sunlight that the trout were feeding on caddisflies because the water
was covered with them. I swapped to various caddisfly patterns.  I managed to catch
two more brown trout neither of which were over 12 inches. It seemed the problem
was the large number of caddisflies on the water. I couldn't figure out why the ant
worked the day before for the guy we meet and us until I lost it.  

The third day we went to an area about fifty yards upstream of where we had fished
the two previous days where I noticed something almost unbelievable. Trout were
lined up by the dozens, side by side, and head to tail in one section of the river.
They all appeared to be the same size which looked to be about 12 inches long.
It looked like a criminal lineup except rather than people, it was trout. My hand
started shaking a little. I didn't know what to do.

I tied on a caddisfly, dry fly adult pattern, and casting from the bank up and
across, let the fly drift down over the trout. The trout ran from the fly or my line
and leader, one or the other. They wouldn't take the fly but rather move out from
under it yet later, return to the exact same place. I realized they were not going to
rise to the surface to eat any fly because they were not rising. They were flashing
every once in a while but not rising to the surface. The water looked about two feet
deep. I changed back to an ant fly which would sink without added weight. Within
the next 30 minutes I had caught three of the small brown trout, all of which were all
about 12 inches long.

Now common sense told me that ants were not drifting down the Firehole
River in any concentration. I didn't even see any on the banks. There were
many caddisflies on the water. Flashes continued until dark but you could fish a dry
fly imitation of a caddisfly (Elk Hair Caddis, X Caddis, etc.) and still not get any takes.

I had been reading the book "Caddisflies" and it occurred to me that the fish may be
eating the caddis larvae drifting downstream or their pupae rising to the surface.
Since caddisflies were hatching, I assumed it must be caddisfly pupae. The trouble
was, I had no caddisfly pupae imitations.

I was back in the fly shops the next morning where I purchased every caddisfly
pupa imitation I could find. That was not a lot of them. If I remember correctly, I
found only three different patterns, none of which I had even seen before. Back
to the magic spot on the Firehole that forth day, I found the exact same lineup of
trout. They would line up about an hour before it got so dark that you couldn't
see them any longer. I tried all three different caddisflies I had purchased. I noticed
that they were all much larger than the ant that I had been able to catch trout on. I
did not catch a single trout that afternoon. I ended up very frustrated. When you
can see dozens of trout in one area and not be able to get them to eat the fly it is
mind damaging. In fact, I could only scare them away for a minute of so, and they
would come right back to the same spot. By the way, that was a clear area of
bottom about four feet wide between the heavy grass that came to the surface most
everywhere else in the river.

Two days afterwards, about six days after this ordeal started, we returned to the
same place at the same time. We didn't spot the first trout. You could see some rise
out in the grass beds every once in a while but the lineup was gone. I still don't
know what was going on. We couldn't catch a trout there the last day we fished that
same area, even on an ant Angie had purchased down on the Henry's Fork that
looked like the same fly (a hook size 20) that the nice guy we met gave us. It
frustrates me to think about it. I really didn't have a clue then why those trout were
there. You would think there was a cool spring nearby but that was not the case,
because I waded in the water and checked the temperature which was 67 degrees.

We have been back to Yellowstone several times since and a few times during
those same dates. I have checked the same spot on the river at the same time of
day but I never found the same thing. I have found plenty of Speckled Peter,
Helicopsyche borealis, caddisflies there at that time and I highly suspect that was
what they were feeding on. They are a size 20, and they are dark brown like the ant
we used. The ant could have been mistaken for the little caddisfly pupae in the low
light conditions. Since then I have caught lots of trout in late June on the Firehole
River on our own
pupa imitation of the Speckled Peter. They could have also been
feeding on the Little Sister pupae but I don't think so. I think I just didn't know
enough about caddisflies that first trip and out of five fly shops in West Yellowstone
there were no decent caddis pupae imitations to be found. Blue Ribbon's little X
Caddis dry fly patterns work fine in some other situations but not in this one. I can
also tell you that a Elk Hair Caddis was worthless in this case.

This was just one of many, many early situations were I realized trout could have
been easily caught provided I knew enough about what was happening at the time.
If we knew what the trout were feeding on at the time and had the right imitation we
could have caught plenty of those trout. When you can watch hundreds of trout in a
line for a few days in a row and know they are feeding on something to the point
you can't even spook them away but for a few minutes, yet you can't catch but a
trout or two, it is pure proof you do not know what you are doing at the time. As you
can probably tell, that situation on the Firehole bugs me years after it happened. It
is also one thing that caused me to study caddisflies and other insects for the next
several years. It is just one of many cases that inspired me to come up with fly
patterns for the various caddisfly species including their pupae and larvae stages of
life. The creators of the thousands of trout flies we mostly have today paid attention
to mayflies and ignored caddisflies. There are plenty of "Purple People Eater Flies"
but as an example, if you ask your local fly shop for a imitation of a Little Sister
larva, they probably won't have a clue what you are taking about. During that same
conversation, the salesman will probably advise you that you don't really need that
fly even though most every tailwater in the states surrounding Great Smoky
Mountains National Park have a few billion of them.

Copyright James Marsh 2009