Mousing for Trout

Fly Fishing at Night: Mousing for Trout

Darkness, moonlight, and big freakin’ brown trout! That is a quick way to summarize fly fishing with mouse flies at night in Colorado. “The freaks come out at night,” sings true on many rivers around here as the big predatory brown trout reserve themselves for nocturnal feeding. Big meals and not a lot of energy expended. For adventurous anglers, fly fishing at night provides opportunities for high rewards. And using mouse flies, well that sure does sound fun. But it does come at a price….

Next time you are fly fishing tries closing your eyes and begin casting using your other 4 senses. It can be a little challenging, we definitely take our eyes for granted. Without sight, fly fishing becomes a whole different ball game.  Fly fishing at night is challenging but like anything, there are tips and tricks and after a couple times it gets easier and easier. Below we outline some basic tips and tricks for fly fishing at night using mouse fly patterns.

Do Trout Really Eat Mice?

fly fishing at night

Little do we know or see as anglers but mice are everywhere. They can be found in the riparian zones of rivers, in grassy fields, and near campgrounds. And mice often swim in the water. Thus, trout being the predators they are, feed on mice regularly. Similar to streamer fishing there can be times of the evening, different parts of the moon cycle, and specific rivers and lakes that are better for fly fishing with mouse fly patterns at night. Also like streamer fishing, anglers have different opinions about what moon cycle and times of the night are best. For this blog, we will focus on mousing for trout on the western slope of Colorado or as we like to call it, “Trout Country”.

When to go Mousing for Trout:

Typically mid-summer around late June is when the mousing really starts to get good and stays good until late fall or when the temps are still not below freezing. For the moon cycle, the darker nights can provide the most productive mouse fishing. A full moon can be too bright for fishing at night. Cloudy nights with off-and-on moonlight have provided the most consistent success. A new moon is always a great option as well. When the moon is high it can penetrate the water and make the trout less likely to come up to the surface. When there is minimal moonlight or the moon is low in the sky it makes the fly visible and the trout more comfortable to eat. Warmer nights are definitely better for mousing, a cold front and cold night can turn off the bite and make for a very cold outing.

Time of night:

As for the time of night, it typically begins right as darkness sets in when the trout are most aggressive. So heading out there around sunset to throw dry flies, and then fishing the first bit of darkness as the moon begins to rise can be extremely productive. This is typically the warmest part of the evening which can also help when cooler temperatures are in the forecast.

Where to go Mousing for Trout?

Since you are fly fishing at night, it is a good idea to go to an area that you are familiar with. A piece of water where you have an idea of where the trout hold and know that access is easy. I’ve found myself at times covering water and ended up casting into a couple inches of water thinking it was deeper. Scout the water and have a plan.

Local areas to check out near the Vail Valley include the lower Eagle River, and Upper Colorado from Pumphouse all the way down to the Lower Colorado below Glenwood, the Gunnison River, and the Blue River. Specifically on these rivers find stretches of water where the current is a little slower, almost walking paced water with bigger boulders and other structure. Oxbows and larger eddies also provide opportunity and of course cutbanks. Cutbanks can be tougher to fish in the dark but if you have fished it before you should be able to try it out at night.

Target Months: July-September.

Best Moon Phase: New Moon or cloudy nights.

Time of Night to Fish: Moonrise or when the moon is not directly above the trout. 

Best Water to Target: Slower, Deeper Water, High Banks or Trees or Tall Grass Lining the Bank.

Recommended Fly Fishing Gear for Mousing:

Now that you have an idea of when and where to mouse for trout let’s go over some recommended fly fishing gear. Your normal trout setups will work just fine, I prefer a 6-weight just for handling the bigger fish, a medium or softer rod can be a lot better than a super fast action stiff rod. The trout will often blow up on the fly and having a rod that has a little bit more give, can mean more hookups. You can really feel the eat with a softer longer rod.  A 9-foot rod is great but a 9 and a half or 10 foot 5 or 6-weight rod would be better. A normal floating fly line with a tapered 2X or 3X. For tippet, typically 0X, 1X, 2X. This fish arent tippet shy, and hooking the bushes is common so having a little stronger tippet doesn’t hurt.

Another option is to try using a trout spey or single spey rod and line. Swinging a mouse across the surface can be an extremely effective way to cover the water at night. If you have a 13 foot 4 or 5 weight, this can be a perfect trout spey for the job.

A for fly patterns, it is good to have a little bit of a selection from some bigger bushy flies to smaller more new age mouse flies. Below is a basic list of patterns to stock up on, my all-time favorites are the Mr. Hankey, and the Mousey McMouseface fly patterns.

Other gear essentials for mouse fishing are waders, boots, warm clothing, forceps, and a good headlamp. Try to find a headlamp that has a red light mode. As this red light doesn’t disrupt the fish as much. But do limit the amount you use your headlamp as it takes time for your eyes to adjust back to the darkness. It is a good idea to bring two headlamps or backup batteries.

Mousy McMouseface
Mousy McMouseface Fly Pattern

Fly Rods: 9 Foot 6 Weight Medium/Slow Action Fly Rod.

Reel and Fly Lines: Weight-forward floating lines with a normal floating leader, 0Xmono tippet, and a trout fly reel.

Recommended Mouse Fly Patterns: Morrish Mouse, Mr. Hankey, Mousey McMouseface, Mad Mouse, Natural Deer Hair Mouse, Trap Mouse, Master Splinter, and Midknight Express.

Techniques for Mousing for Trout:

Now that you are ready to hit the water for the midnight mission to find that brown trout of your dreams here are a few techniques to keep in mind. Keep your fly casts shorter than you would think, it is easier to control a shorter cast so cast directly across the river and then begin the retrieve.

When retrieving a mouse fly, every angler has their preferred methods, but I believe the best way is to experiment and find what works best for you. Mousing is not pretty so don’t think too hard about the cast and focus on the retrieve. If you have enough current a lot of times you can let the current swing your mouse fly. Add in a little wiggle to the tip to make that fly dance like a mouse swimming across the water. It is essential to keep tension on the fly for when a trout tries to eat it.

Another very effective retrieve is to put the rod under your shoulder and begin to retrieve the fly line with both of your hands in a slow but very very consistent motion. When you hear or feel a fish keep that fly line tension tight and pull to set the hook.

Blow Ups vs. Hook Ups

Most evenings, you will be able to experience some “blow-ups” which just means that the fish tried to eat the mouse fly and you didn’t come tight to it. Most of the time this is not angler error as the fish misses the hook, it is too small for the large fly. But sometimes if you don’t have tension on it the fly will come free, so make sure that you have complete tension on that fly and if you do have your rod tip down you can set it like a streamer eat. It can be frustrating at times but if the big one wants to eat the mouse fly most often it won’t miss!

With all success comes some failures.

Mousing for trout at night is not for everyone. You have to be committed to it and have a plan of where to fish. There will be nights with no success and you may have been doing everything right. Sometimes the fish aren’t there or the light isn’t right or the trout are not being aggressive. Then there will be nights when the bite is really hot. Keep pressing and trying out new techniques. There is no right or way to fish at night and no one is watching.

If you are interested in booking a guided mouse fly fishing trip you can find more information on it here.

Patrick Perry, Former Float Fishing Guide, and Content Contributor, @patperry