The Firehole River is like no other river in the park, or in the world for that matter. Beginning in Madison Lake at nearly 8200 ft, the Firehole meanders its way through some of the most spectacular thermal features in the park. Flowing basically north, the Firehole offers the fly fisherman (fly fishing only) a variety of water types before joining the Gibbon to form the Madison River. Riffles, runs, whitewater and meadow water types are all available to fish.
Fishing the Firehole is not always an easy endeavor. Since it is one of the most photographed and easily accessible rivers in the park, its fish see a lot of people and can become quite smart shortly after the beginning of the season. For the first week or so after opening just about anyone can have success on the Firehole. Nymph fishing is almost mandatory when the Firehole opens, but some years you may see some dry fly activity.
The first place most people see the Firehole is where it crosses the main highway as it enters Biscuit geyser basin. There is a little bit of riffle water right around the bridge which fishes very well with nymphs, then it flows into a grassy meadow where it takes on meadow stream characteristics. Here it is a classic meadow stream complete with grassy undercut banks where you can easily see fish rising to dry flies. Dry flies, nymphs and soft hackles all work well here. Most anglers prefer to fish this type of water with dry flies and will often wait until a hatch starts before fishing.
There are a number of other places to fish the Firehole, and the location depends on the type of water you like to fish. Other classic dry fly areas include the Fountain Flats road and the area around what is often referred to as Muleshoe Bend. The fact is that there is so much good water to fish on the Firehole it would be difficult to find a place that didn't offer action with some sort of fly.
Success on the Firehole depends on how well you understand the river and how observant you are. In many places you need to be very sneaky and execute an almost flawless cast. These fish can be quite particular and will sometimes only take the particular insect they’re feeding on. In other places, such as riffles, you can use a more suggestive pattern. Although you can have success on the Firehole by yourself, this is one of the great rivers to go out and learn with a guide. There are so many water types here that you can learn a variety of fishing methods in a single day.
One important element when fishing the Firehole is to be prepared for both the fishing and weather. While you may be tempted to use a light short rod, you’ll find a 9 foot rod for a 5 weight line is best for the often windy conditions. A 9’4x leader will work well most of the time.
June tends to have very unpredictable weather in this part of the country. The Firehole often fishes best in adverse weather, so if you are prepared for it, you can sample some of the best the Firehole has to offer.
The first hatch of the year is the BWO (Blue Winged Olive). These little mayflies generally start hatching just when the Firehole opens (they may actually start earlier but the river is closed at that time) and last into June. BWO Parawulffs and Hi Vis BWO are both effective at that time. The PMD hatch starts in earnest about the beginning of June and lasts into the beginning of July. On this river this insect is larger than it is on many rivers in this area, often it is about size 14, and their hatches can be prolific. Their color varies a bit from year to year but often they are more of a bright yellow in color. There are a number of good PMD patterns on the market and much depends on how picky the trout are. The PMD Parawulff is one of my favorites but other slimmer patterns may be needed for more selective trout. Midges are always present but not nearly as important when the PMDs are out.
Caddis hatches occur throughout the summer and into the fall. Activity is generally best in the evening. The best patterns are the X-Caddis and Peacock Caddis. Soft hackles and Sparkle Pupa are both viable options at caddis times.