Mousing Montana Fly Fishing

Missoula Night Fly Fishing – Mice and Big Streamers

It’s 8:30 pm on a late July evening in Western Montana. You just got done with a short after work trip to the river, throwing a dry and putting a few smaller fish to hand, then switching it up to a streamer, but no slam pig brown like you’ve always dreamed of. The sun is just starting to tuck behind the mountains, so you figure you’d better head back towards the car. . . or should you? Is the best trophy trout fishing of the day about to begin? Is that monster of a brown trout just starting to slide out from a deep hole to feed? Well, there’s only one way to find out.

Morrish Mouse


One of the most overlooked methods of fly fishing for big trout around Missoula starts when the sun goes down. It may seem foolish and difficult to fumble around attempting to cast in the dark, but the payout can be extravagant. First, let’s establish why this works, and why it’s worth giving a shot. Big trout, and I mean BIG trout (23-32 inches) didn’t get big by being stupid. After living in a system for anywhere from 7 to 20 years, they know where and when they are in danger from predators, they know what actions put them in a vulnerable position, and they know one simple solution to eliminate these life-threatening factors. Eat. At. Night. Simple as that, feeding after sundown allows big trout to roam nearly any part of the river as they wish without a care in the world about the eagle that lives a quarter mile upstream. However, protection is not the only reason that huge trout choose to feed almost exclusively at night, there is another factor that is more seasonal. As you may have noticed the last time you fished the river in 100 degree weather, trout aren’t too fond of hot water temps. The biggest and smartest fish in the river are no exception. These fish live with 4 things in mind: get big, stay big, make babies, don’t die. The ‘stay big’ portion of this lifestyle is not particularly complimented by exhausting vast amounts of calories trying to chase baitfish through the shallows under the scorching hot sun. The air becomes cool at night in the Missoula area, and so does the water. Yet another reason why the 10+ pound trout of your dreams isn’t sipping BWOs at 2:00pm.


Now that we’ve discussed why this works, lets address how. There are two commonly used methods when it comes to fly fishing at night; mousing/topwater and streamer fishing. In most freestone rivers like the Bitterroot River, Blackfoot River and Clark Fork River, when trout reach a certain size, mayfly nymphs and caddis flies aren’t going to sustain the calorie intake that these pigs require. When the fish reach this point in their life, some will start to shift from a BMI (Benthic Macro Invertebrate) diet, to a baitfish and juvenile fish diet. Not only this, but these trout will also predate on mice, rats, small water mammals, frogs, crawdads, snakes, birds, the list goes on. Anything that offers a significant number of calories, a large predacious trout will eat if it can get its jaws on it. That being said, larger 4-7 inch articulated streamers have become a standard imitation for these large piscivorous trout, and anything from a single hook Moorish Mouse to a triple articulated rat pattern stripped across the surface will go as a rodent imitation. Oh, and ideally bring at least a 6 or 7 weight rod or you’re ‘gonna have a bad time’. Now, it’s not necessarily true that one of these fly selections will work better than the other, because when a trophy trout is the target, it’s more-so about being in the right place at the right time. However, as exciting as it is to hear a 6 pound brown Trout break the silence of the night with a belly flop on a mouse pattern, the number of hookups are less than ideal. If comparing the hookup ratio of a mouse pattern to a streamer, it’s probably 1:5. . . Regardless of which fly option you choose, the strategies that follow both are relatively similar. First off, it all starts with finding the right body of water. You need to find a system that has big fish potential. This can mean a few things. . . the system has at one point or another produced a giant fish or two, the system regularly produces larger fish (say 18-22 inch trout in this case) and you’re looking to uncover something greater, or maybe something as simple as a big fish story. Two crucially important factors that arise while night fishing rivers, is familiarity with the water, and finding safely wadable water. Don’t go trotting out onto a river you’ve never laid eyes on before in the pitch black. Not only can this be incredibly unsafe, but you also will have little clue what you’re casting to, tremendously lowering your efficiency. Keep in mind, it’s important to keep your headlamp off as much as possible, so casting into complete darkness is much easier if you’ve walked the water a time or two in the daylight. Additionally, try and choose a stretch of water where you can either easily navigate the bank, or walk through shallow and calm water that won’t sweep you off your feet and take you for a midnight swim. Now, with disclaimers out of the way, lets say you find a familiar stretch of river that you are convinced will produce a 28” brown trout. Focus on fishing moderate/slower pace water, anywhere near obvious structure or cover such as undercut banks, overhanging trees, downed logs, and rip-rap banks. Another major river feature that should be noted while night fishing, is big shelfs and drop offs. Often, large predatory fish will sit down on the deep end of a drop off during the day to rest. When nightfall hits and they’re ready to feed, they will move up onto the shelf and scan the flat water for minnows and juvenile fish . . . so, don’t be hesitant to pull a streamer or mouse through a stretch of knee deep water. Additionally, big fish will also move into side channels and sloughs where their prey has less room to escape.

Mousy Mcmouse Face. One of our favorite mouse patterns.


From here, there’s only a couple things left to consider; commitment and persistence. Night fishing is different, and not particularly convenient or appealing to the average angler. However, it is by far the most effective manner of targeting big fish exclusively and not worrying about numbers. Furthermore, the determination to pursue a big fish comes with some downfalls. Other than the few giants, most fish usually stop feeding around sunset. This means you’re going to get skunked more times than anyone likes to admit along the journey of chasing a trophy. Those willing to bite the bullet and put fishless (and sleepless) hours on the clock are the ones who will be rewarded. So . . . next time you hit the river for evening outing of fly fishing, bring a few streamers, a couple mice, and a headlamp. Stay a few extra hours and you may be surprised what kind of magic happens after the sun goes down.

We do offer guided fly fishing trips in Montana for Mousing. Due to safety of issues of fishing at night we typically start at first light in the morning which can be one of the best times to mouse. If this is something you would like to do then please give us a call at 1 (406) 728-7766.

Additional Night Fishing Resources

Pale Morning Duns and Pale Evening Duns

Why are we grouping these two together, when they’re so taxonomically different? Because the same fly that works in the morning will work in the evening, so with the same imitation, we lump them together. The PMD’s and PED’s are the first hatches post run-off that can be wader friendly for fly fishing, and the PMD’s are a classic mayfly hatch. PMD’s have been known to darn near blanket the waters on the Clark Fork River and Bitterroot River, and they’re also very prevalent on Rock Creek and the Blackfoot River. This is a very important insect for Missoula rivers and it’s fisherman.

When we say classic mayfly hatch, it comes from the view many anglers take, declaring matching the hatch as the premiere challenge in fly fishing. During a blanket hatch, the fish definitely key in on certain stages of emergence and adulthood. Because of the feeding complexity, the PMD is a hatch where you buy flies wide and shallow. That means if you buy 6 PMD’s, get two parachutes, two cripples and two emergers. That way, you’re better able to match the insect stage being focused on, instead of having six adults when the trout want cripples. It’s not a bad way to buy flies at any time, but especially important with an abundance of insects. The PED’s aren’t always as abundant, but since you’ll already have a wide array of flies, you’ll be ready!

The PMD nymphs are crawlers, and very poor swimmers. After bottom release, their ascent to the surface is quite feeble. The long, slow rise to the surface gives trout time to gorge, and during emergence trout may be found higher in the water column, following nymphs to the surface. The PMD emergence is one time you may not want your nymph on the bottom, but suspended a little higher up. It’s an exciting way to nymph, sight fishing to suspended fish. A jig Pheasant Tail or a Racing Gold Perdigon is effective at this time. After ascent, PMD’s emerge from their shucks a couple of inches from the surface and finish floating to the meniscus to emerge as adults.

Trout can very specifically target PMD’s after emergence from their shuck but not yet to the surface. Pay close attention to the rise form. If there are no bubbles trailing the rise, chances are very good the fish didn’t break the surface with its mouth, but with its back. Floating a dry fly over a fish that’s not coming to the surface is exceptionally frustrating! If there are no bubbles, attach an emerger or a nymph on a dropper about 4 inches long. This will allow the fly to sink just under the surface film, but not too deeply. You’ll take a lot of “risers” this way.

With the PMD, it’s a good time to talk about the difference between a cripple and an emerger. Our best answer is about 1 second. Mother Nature is not always kind, and when the emergence process is interrupted, the insect quickly goes from emerger to cripple. It’s not as complicated as some people make it out to be. Both cripples and emergers are found in the surface film, and often imitated by the same fly, like a Film Critic. The PMD, with its slow emergence, provides multiple opportunities to use a fly in the film. A rise form to a fly in the film may or may not leave bubbles. Just adds to the puzzle!

Once a PMD has broken through the meniscus and emerged, it must wait for its wings to dry before flying. Depending on weather conditions, an adult can ride on the surface for quite a long distance, again providing the trout with quality feeding opportunities. A Tiltwing Dun or simple parachutes are excellent imitations for the adult.

So let’s make things complicated. PMD’s and PED’s also fall as brown spinners, which is imitated by the Hi-Vis Rusty Spinner. A spinner is a spent adult, returning to the water to finish its life cycle. These spinner falls can occur early in the morning, late at night, or, our favorite, during the hatch. So quite often, you will have the option of Rusty Spinners during the emergence, which adds complexity to matching the hatch. Again, we return to the classic concept of a mayfly hatch. You can find a group of rising fish, and while one may be taking emergers, the fish next to it may be taking adults, cripples or spinners. Which can make matching the hatch an interesting proposition. But isn’t that why we choose to pursue a fish with a measured IQ of 4, to keep things interesting!

Fisherman and guides are pretty spoiled in Missoula, MT having so many great hatches for fly fishing and the PMD is one hatch that last longer then most. This makes it a very important insect and there should be plenty of different stages of imitations in your fly box.

Additional PMD and PED Resources

Green Drake Hatch Montana

Green Drakes in Missoula

The Western Green Drake is a good hatch for fly fishing in Missoula, MT, but not the easiest to predict. It doesn’t come off as heavily as other hatches in the area, but can be strong in certain places at certain times. As with many early season mayflies, the hatch is triggered by water temps, and due to factors like runoff, rain and varying weather, the Green Drake isn’t a hatch you can set your watch to. But they’re a sizable bug, and when they start hatching in early to mid-June, they’re big enough to pull fish off of the Salmon Flies and Golden Stone! So it pays to have some Western Green Drake imitations in your box, especially when the weather is cloudy.


There are two main species of Western Green Drakes, Drunella Grandis and Drunella Doddsi. D. Grandis max out at 16mm while D. Doddsi maxes out at about 13mm. We have both on our waters, imitated by the same pattern, in size 10 or 12, and applies to nymphs and dries equally. The nymphs don’t hatch at the surface, they hatch about a foot below the surface, and then float to the top to use their wings to break through the surface film. While this emergent phase may be critical on rivers like the Henry’s Fork, where the Green Drake is a blanket hatch, in Missoula the sparser nature of the hatch means fish keying on the Drakes are a much less fussy.


Using the wings to break through the surface film causes additional stress to these insects. When these insects do emerge, their wings are pretty beat up, and many of the adults don’t actually make it to the stage where they can fly off the water. A Green Drake Cripple, such as a Sir Francis or a Quigley Cripple are excellent imitations of the drakes that don’t make it.


The Western Green Drake uses a liquid to fill the veinations through its wings. That process takes time. And depending on air temperatures, the Green Drake wings can take a long time to dry. On colder days, the bugs may float for over a minute before their wings are full and dry and capable of flying. The dry fly is a subject of some debate amongst tyers and fishermen. In Missoula, Green Drakes hatch when the rivers are running pretty big. On the Blackfoot River and Rock Creek, you may want to use a Green Drake pattern with strong flotation, like a Hairwing Green Drake. But when Green Drakes hatch on the Clark Fork River or Bitterroot River, which are much lower gradients, use a more imitative pattern like a Carnage Green Drake or an Tilt Wing Green Drake. That’s not to say that the flies listed are river specific, we’re simply saying that a big, bouncing river will sometimes need a higher floating fly than a calmer river might require.


The Green Drake isn’t always the friendliest of hatches for the wading angler. The rivers are big when it starts coming off, and sometimes a wading angler simply can’t get to where the insects are hatching. As with most mayflies, if you can set yourself up downstream of a good, strong riffle, these crawler nymphs will hatch down into the slower water often found below riffles. And of course, in all high water, the fish are hugging the banks, looking for the softer water. With an insect that may float for a minute on the surface, it may not be critical to be near where they’re hatching, only to be near where the fish can find
soft enough water to rise!

Additional Green Drake Resources

Guided Fly Fishing Missoula Montana

Take a Cloud Day!

If you ski, or know any skiers, you know the concept of a powder day. When 10” of beautiful powder falls on a Tuesday night in February, In Missoula, MT, a certain group of diehards fisherman are prepping their reason they can’t work the next morning. Bad stomach, headache, the dog ate my homework, all these are employed by erstwhile employees as they bag work and go skiing!

The Missoulian Angler Fly Shop and guides are well aware of the summer version of a powder day. It’s called a cloud day. We’re big sky country, and when the sun comes out for good in late June, the sky is azure blue with little rest from the sun. For the angler or the fish! Trout fishermen have sunglasses. Trout don’t even have eyelids. When the sky is high and bright, trout show up like beacons to overhead predators. Many trout choose to stay close to the bottom where the sun is less debilitating, and depth provides protection from overhead predators even when the hatch is going on.

Watch the summer weather reports closely in Missoula, MT. When they call for a cloudy day smack in the middle of a sunny spell, start thinking of your reason not to go to work. A cloudy day is the perfect storm for fly fishing. Mayflies will hatch in greater numbers when they have cloud cover. With no eyelids, the trout are more comfortable in the lower light. Additionally, cloud cover affects the ability of predators to locate prey in the water. Combine more insects, less predation and less ocular stress, and you have so many more fish moving to so many more insects on a cloudy summer day it can look like a battalion of kids tossing rocks in the water. As Missoulians well know, a cloudy day in summer is a rare treat for fisherman. Much like 10” of powder. So take advantage! Work on those symptoms, sound convincingly hoarse and stuffy, and then enjoy some of the best summer fishing you can get.

Spruce Moth Fly Patterns

MAngler Spruce Moth | Tie your own!

 DIY MAngler Spruce Moth 

As the spruce moths are starting to make a comeback, we’re all scrambling to get our hands on some. Ron Beck has a unique way of tying them, and we have a video to get you through each step. These moths are rippin’ lips on the Blackfoot and the Clark Fork, as well as Rock Creek. If you’re in need of supplies to tie them yourself, or you have any come on in and we’ll help you out! 

Don’t Hate

Lot’s of people look down on fish that aren’t trout.

What a Sucka

Why? I don’t. The Suckers, The Pikeminnows, and the Grand White Fish. They eat the same things trout do.

Northern Pikeminnow

They don’t just roll over when you hook them either, and lots of time you’re not sure it’s not a trout until you can see it.

Northern Bonefish

I say live it up. Use them as practice for landing fish. At least you know your fly is working. And whats cooler than a fish without teeth that eats a streamer?

The Pikeminnow

So don’t hate on the “Non-Trouts”. They are fish too.

It’s absolutely beautiful out today. Get out and go fishing.

-The MAngler