Guest Blogger: Mike Cline, Bozeman, Montana

Fishing the rise and fall of the Firehole successfully in early June has always been a challenge. Having talked with many anglers who are disappointed with the lack of hatches and failure to catch decent fish on a regular basis, I became convinced that traditional methods were fruitless. Anglers waiting for hatches waited in vain. Anglers drifting small nymphs in deep waters were frustrated for the lack of takes. Anglers swinging small buggers and soft-hackles on floating lines (a commonly recommended approach) never get those flies in front of fish. When the water is high on the Firehole, the fish, especially the browns, are taken close to the bank where they shelter in deeply submerged undercuts. You have put a fly inches from the bank and down quickly in the swift water. The take may come immediately or as the fly swings out into the current. If you are fishing along a deep bank letting the fly swing all the way to the bank and slowly retrieved may lure a fish out of an undercut you are standing near. After several years of perfecting this technique, it was time to devise a fly that would excel in the deep, tea colored waters of the Firehole.

The fly was inspired by the Australian “Shrek” (Joe Riley, Australian World Fly Fishing Team; circa 2005) and the “Big Hole Demon” (Dan Nick Naranchi, Dan Bailey; 1964). The large profile, bright mylar body and intense contrasts from the badger or furnace hackle make it effective in luring fish out from deeply submerged undercut banks and the bottoms of deep pools. Its light weight makes it easy to cast accurately at distance with sink tip lines and short leaders. Long, accurate casts are necessary in bank full rivers where wading is difficult if not impossible. I typically fish this fly with a 5 weight, 150 grain sink tip and a 3-4’ OX leader. I dubbed it the Firehole Demon. Yes, it is nothing less than a brightly adorned woolly bugger; but is it effective. The pattern can be tied in a wide variety of colors from intense black to bright creams. Tails should display a distinct contrast between the top and bottom. Badger or furnace saddle hackle provides a distinct body contrast. The Polar Flash body will reflect the tail and hackle colors creating unique contrasts within the fly and is highly visible in stained water.

When the water is really high, as in the image above, a Firehole Demon tied on a number two 839 Firehole Stick is a big meal for a big brown. As waters drop and the river clears a bit, flies on number 4, 6, 8 and 10 Firehole sticks prove equally effective.

However, once flows drop toward 100 CFS at Old Faithful, the sink-tip and bright flies lose their advantage. As the flows drop and the days get longer, the aquatic vegetation gets more sunlight and grow so to speak like weeds. As flows drop the water warms more each day increasing the amount of aquatic insect activity. Although undercuts are still popular haunts for decent fish, more fish move out into the middle of the river around vegetation and streamside eddys where insect activity get concentrated. By the last week in June, daily water temperature in the Firehole will reach levels that make the fish lethargic or escape to cooler tributaries.

I’ve talked to a lot of anglers who avoid the high-water periods on the Firehole because they are unwilling to use or unprepared to use big, bright flies on sink-tip lines on the fabled Firehole. Those that I can mentor on stream with my technique usually catch fish quickly and are sold. I even encountered an angler (I think visiting from Colorado) who was peppering the high-water randomly with a large dry fly (to no avail). I suggested going to a large streamer and offered up a few Firehole Demons to help him along. “No thanks, I don’t want to catch a fish on a streamer” was the strange response. His loss.

The Rise and Fall of the Firehole turned out to be extremely productive for me this year with well over 100 fish, many in the 16” class and one at 18” falling to a Firehole Demon in the first three weeks of the season.

Note: The Firehole Demon not only proved effective as a fly pattern, the Firehole Outdoors Firehole Stick #839 hooks performed exceptionally well. They proved to be the ideal hook for this pattern and use in the park which requires barbless hooks.


Hook: Firehole Stick #839BL, barbless heavy streamer hook, sizes 2-10
Thread: UTC 140 Denier Fluorescent Orange
Weight: 10-15 turns of lead-free .015 wire at mid shank
Undertail: Clump of Angel Hair trimmed short about hook gap length
Tail: Two shades of Finn Raccoon with the lighter shade on the bottom (Fox can be used for smaller versions)
Tail Flash: Several strands of Polar Flash or Flashabou Weave
Body: Polar Flash or Flashabou Weave, sealed with UV cured cement.
Hackle: Badger or Furnace (natural or dyed) saddle hackle.

Tying Instructions:

  1. Wrap a thread base from the hook eye to the hook bend. Apply 10-15 turns of .015 lead-free wire mid shank. Overwrap with a layer of thread to secure.
  2. Select 4-5 full strands of Angel Hair and fold in half. Secure at the fold on top of the hook bend. Fold the Angel Hair toward the hook eye leaving ~ ¾” beyond the hook bend and secure with a couple of wraps. Fold the remaining lengths of Angel Hair back toward the hook bend and secure with a couple wraps. Trim the clump of Angel Hair square to ~ approximately hook gap length.
  3. Select a slender clump of Finn Raccoon fur and remove any fuzz from the butt ends. The tail should be slightly longer than hook shank length. Hold the clump of fur on top of the hook to determine where to trim the butt ends. With the thread slightly behind the hook eye, start securing the Finn Raccoon fur on top of the hook. Make even wraps all the way back to the hook bend. It is essential that the underbody be uniform and smooth as a base for the Polar Flash body.
  4. Select two strands of Polar Flash, fold in half and lay on top of the hook bend. Secure with thread and trim the flash to the length of the tail.
  5. Repeat step 3 with another slender clump of Finn Raccoon maintaining the smooth underbody.
  6. Select a large Badger or Furnace saddle hackle and tie the tip in along the hook shank leaving the thread at the hook bend.
  7. Select 4-5 complete strands of Polar Flash or Flashabou Weave. Lay the strands on top of the hook with the mid-point of the strands at the hook bend. Secure with 2-3 thread wraps. Fold the mylar in half and gather all the ends in one hand. Wrap the flash around the hook shank with even pressure. The first wrap should be back toward the hook bend to cover some of the thread wraps. The flash will flatten out a bit as you wind it forward making it easy to cover the entire body. At the hook eye, secure with several thread wraps and trim.
  8. Apply a thin, even coat of thin UV cured cement to the body, but do not cure yet.
  9. Wind the saddle hackle forward with even wraps. The dark hackle stem should contrast sharply with the mylar body. Take a few extra turns of hackle at the hook eye to create a dark head. Secure with a few thread wraps.
  10. Before trimming the hackle butt, cure the UV cement. This will help bind the hackle to the mylar body.
  11. Trim the hackle butt and create a clean head with the thread. Secure with a whip finish or double half hitches. Finish with Flex Cement.


  1. Mike…. Thanks for sharing the story of the firehole… I have been fly fishing for a short time now and I have a great desire to see and fish great new places that are outside my home state(GA)….next summer in June 2019, my teenage son and I am going to be taking a vacation in the West and Northwest States… would you please share with me some information about easily assessable places that have been fly fishing really good places that we can get to and fish?… Thanks again for your help and advice… The information on this will be really helpful to me and my son…he will not be flying fish in..
    Probably using his regular rod and reel spinning… but I am going to be using my fly fishing set(s).. I moved back home to GA back in 2009, from Wausau WI. That is the time I got hooked on fly fishing.. not much fly fishing around here in Augusta Georgia… lots of golf ing though(master’s tournament)….

    1. London

      I’ll get Kate to send you my email. I am happy to share advice about SW Montana fishing.


  2. Book a guided trip on Missouri River out of Craig, Montana. Amazing fishing. Headhunters fly shop and guides are awesome. Book early up to a year in advance. Look into guided trips down the Madison and Gallatin Rivers as well out of Ennis and Bozeman. The Yellowstone River in YNP opens July 15, which is also a great time for dry fly fishing. .

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