Copyright 2015 James Marsh
Hatches and Flies for the Firehole River (YNP)
Blue-winged Olives, mostly Baetis species, hatch from opening day until the end of the
month of June in the Firehole River. The are bi-brooded and will hatch again staring about
the first of September and lasting until the season ends.
You may find some Little Black Caddisflies, Grannon species, hatching from the opening of
the season until the end of June. The Spotted Sedges usually start hatching the time the
season opens. These caddisflies will hatch off and on until the middle to the end of
October. White Millers will start hatching about the time the season opens and last through
June. There will be another hatch that starts about the last week of August and last
approximately a month.
The Green Sedges hatch starting about the first of July and last until the middle of
October. The Little Short-horned Sedges will hatch throughout the month of June, July and
August. Little Speckled Peter caddisflies will hatch from about the middle of June to the
middle of July.
The PMDs, or Pale Morning Duns, start about the time the season opens and last through
the middle of July, depending on the weather and water condition. The hatches and
spinner falls are both important.
There will be some Green Drakes that hatch from the for about the first three weeks of
July. These aren't huge hatches. The Brown Drakes start at the same time for about three
weeks. They are found in the slow to moderate flowing meadow sections of the Firehole
In the fast water sections, you will find Pink Ladies, or the Eperous species or Yellow Quills,
hatching during July and August. March Browns also start hatching in the faster water
sections about the first of June and last until mid July. Flavs, or Small Western Green
Drake mayflies, will hatch in the moderate water sections from about the middle of July to
the first of August.
Mahogany Duns will hatch from about the first of June through the middle of July. These
are small, hook size 18 mayflies that some anglers call Blue Quills.
Salmonflies can usually be found in the fast water sections (mostly in the canyon_ of the
Firehole River during the month of June. Yellow Sallies, or Little Yellow Stoneflies, hatch
during the same time period.
Terrestrial insects are very important trout food on the Firehole River, especially in the
meadow sections. Imitations of grasshoppers, ants and beetles will catch trout from about
the last week or two of July until the middle to end of September. Don't overlook the flying
ants. They can swam and fall on the water anytime during the summer so be ready for
them if they do.
The Firehole River has its share of sculpin, minnows and other baitfish species. Streamers
work good during very low light conditions or when the water is high and stained from the
We have "Perfect Fly" imitations of every insect that hatches in Yellowstone National Park,
including the Firehole River. Many of our flies were developed there. If you haven't already
done so, we encourage you to give them a try. The not only are the most realistic flies you
can buy, they are the most effective at catching trout. See our Firehole hatch chart.
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Firehole River (YNP)
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