Insects and other foods the trout
should be eating:
1. BWOs (Little BWOs)
3. Little Winter Stoneflies
4. Little Brown Stoneflies
5. Quill Gordons
6. Blue Quills
7. Little Black Caddis
Most available - Other types of food:
8. Sculpin, Minnows (Streamers)
Getting Started - An Example Of Why Knowing What The Trout Are Eating Can
Make A Big Difference In Your Success
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 on video and later log the video 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. We stopped at the nearby Firehole River. 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
the trout in the other streams but by about the end of June, the water usually get 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. The problem was, we just didn't know it. There were only a very few anglers along the river
when we drove up the stream. According to my log, 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 black ant. 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 for ants but couldn't 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 hook 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 River outside the park about two hours earlier than the
day before. It was quite obvious in the bright 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 was 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 worked well for 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.
There I noticed something almost unbelievable. Trout were lined up by the dozens, side by side, and head to
tail in that 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. There were at least a hundred trout within sight.
I tied on a caddisfly - a dry fly adult pattern and cast from the bank up and across, letting the fly drift down
over the trout. The trout all ran from the either the fly or my fly line and leader. They wouldn't take the fly.
They would just quickly move out from under it. Later on closer to dark, when I returned to the exact same
place, it began to occur to me that they were not going to rise to the surface to eat any fly because they
were not rising. They were flashing under the water appearing to be eating something every once in a while
but they 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 caught three of the small brown trout, all of
which were about 12 inches long.
Common sense told me that ants were not drifting down the Firehole River in any concentration. I didn't even
see any ants on the banks. There were lots of caddisflies on the water. Flashes of the fish eating something
continued until dark but I 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 maybe their pupae rising to the surface. Since caddisflies were hatching, I assumed
it must be caddisfly pupae. The trouble was I didn't have any caddisfly pupae imitations.
I was back in the fly shops the next morning and purchased every caddisfly pupa imitation I could find. That
was not a lot of them. If I remember correctly, I found only two or three different patterns, none of which I had
We went 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 caddisfly pupa imitations 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 will damage your
mind. In fact, when I scared them away, they would be gone for a minute of two and come right back to the
same spot. By the way, that was a mostly 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 went on during that time. We couldn't catch a trout there the last
day we fished the 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 still 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 wasn't the case because I waded the water in the same spot and checked the temperature which was 67
We have been back to Yellowstone many 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 had learned;
much more about caddisflies, and later on at the same place and time of day, I found plenty of Speckled
Peter, Helicopsyche borealis, caddisflies there. I highly suspect that was what they were feeding on. They
are a hook 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 that time, 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. I just didn't know enough about caddisflies
that first trip and out of five fly shops in West Yellowstone, there were not any decent caddis pupae
imitations to be found. Blue Ribbon's little X Caddis dry fly pattern worked fine in some other situations but
not in this one. I can also tell you that an Elk Hair Caddis was worthless in this case.
That 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, I'm positive 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, you know something there interest them. When
you can't catch a few of them, it is just absolute proof you don't know what you are doing at the time.
As you can probably tell, that situation on the Firehole River bugs me years after it happened. It's also one
thing that caused me to study caddisflies and other insects for the next several years. It is also just one of
many cases that inspired me to come up with our own Perfect Fly fly patterns for the various caddisfly
species, including their adult, pupae and larvae stages of life.
For the most part, the creators of the thousands of trout flies on the market today, paid some attention to
mayflies but completely ignored caddisflies. 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
United States has a few billion of them.
Get started the right way. Start learning all you can about the food trout eat to survive on. If you don't, you
will forever be relying mostly on trial and error and a lot of pure luck.
Copyright 2013 James Marsh
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Which Flies To Use - Coming Week
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