Fishing Mouse Patterns for Big Trout

Mice may seem too large a meal for trout, indeed many anglers think of them more as bass prey than trout food. Many trout populations do indeed feed heavily on mice and other small rodents though.

Despite trout’s reputation for being picket eaters, they are often quite opportunistic. Large trout occupy a spot relatively high on the food chain, and will readily feed on a mouse struggling to cross a river.

It’s often only the largest trout that frequently prey on rodents, and this most commonly happens at night. This would be why many anglers don’t see it for themselves. It’s a small subset of trout anglers that fish in the middle of the night. This can be the most productive time to fish for big trout.

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Mouse Patterns

One of the most productive fly patterns for imitating rodents is the Morrish Mouse. This pattern has a few unique things going for it over other patterns.

• The pattern uses both deer hair and foam, making it that much more buoyant than deer hair only patterns.
• The foam forms a little lip at the front end. This moves additional water, making the flys wake that much more noticeable to fish. This lip even allows you to fish this pattern somewhat like a popper if you like, with short sharp strips.
• There are only three ingredients in this pattern (deer hair, foam, and whatever you use for the tail), making it a fairly straightforward pattern to tie. This is important as you’ll likely be fishing the Morrish Mouse fly at night, which tends to result in an increased number of flies lost to overhanging trees and bushes. Even though the fly is a straightforward tie, spinning deer hair can be a bit time-consuming.

You can tie a very similar pattern palmering rabbit strips instead of spinning deer hair. This is a quicker and easier way to tie a similar pattern. Unfortunately, the fur gets waterlogged more quickly than deer hair, causing a heavier fly. This makes casting the fly more difficult, and you’re likely to end the night with a sore arm. If you’re more concerned with a quick tie than easy casting (IE you lose many flies, which is made even worse fishing at night), this is a valid alternative. This pattern also sits a bit lower in the water than the deer hair version, which can reduce the number of short strikes if that’s proving the be a problem.

The morrish mouse fly pattern certainly isn’t the only mouse pattern that will work.  There are many other patterns that imitate a mouse quite well. I find there isn’t much need to carry a wide assortment of mouse patterns though, so I stick to the pattern I’ve found fishes the best (morrish mouse). The underside of most mouse flies look quite similar anyway.

What I do find useful, is to carry the same mouse fly in different sizes. I have morrish mice in sizes to mimic shrews, and mice when targeting trout. I find trout respond best to smaller shrew sized patterns, but I’ve caught some nice fish on mice size flies as well.

The only reason to go bigger is if you’re fishing something other than trout (mostly pike or musky, but bass may take something that large as well) If you’re imitating something the size of a rat or bigger (like a baby muskrat), you’re going to need to use an articulated version of whatever mouse pattern you choose.

What Time to Fish Mouse Patterns for Trout?

Definitely at night, and to a lesser extent other low light conditions. Not only are mice more active at night, but the biggest trout in the river tend to be most active at night as well.

I find the big trout in a river start feeding heavily in the first hour after dusk. I’ll often take this opportunity to fish streamers, but mouse patterns work well at dusk aswell.

Mousing really starts to shine once the last remaining light from dusk fades. The darker the night, the more successful mousing seems to be in my experience. I suspect this is because the trout don’t have great night vision, and are relying much more heavily on their lateral line to locate prey. If its clear skies with a full and bright moon I tend to lean more towards fishing streamers.

Fishing mouse patterns is just the type of fishing to trigger a trouts lateral line. Most methods of fishing these patterns cause much more commotion than other fly fishing tactics.

How to Fish Mouse Patterns for Trout?

Where to Cast?

If you can manage without getting the fly snagged, try casting onto the opposite bank and pulling the fly into the water. This mimics a mouse crossing the river from the very beginning. It’s not natural for a mouse to plop down in the middle of the river. The exception is if there is an undercut bank or overhanging branch. This brings me to the next method of casting.

Identify areas where a mouse might accidentally fall into the water. Overhanging branches and undercut branches are ideal areas. Then cast the fly so it lands under these areas with a loud splash. This mimics a mouse that lost it’s footing and has fallen into the water. Actively feeding trout will have a hard time passing up such a large meal obviously in distress.

The Retrieve

There are two main ways to fish a mouse pattern. You can fish the pattern slow and steady, which mimics a mouse casually swimming across the water. You can also fish the fly hard and fast, which mimics a drowning mouse.

Both methods work, but I find the slower retrieve works more often. The retrieve involves short, consistent strips. This should result in the fly “swimming” across the water at a fair consistent speed. You can vary the speed to find what works best on your waters, but look up videos of mice swimming to get an idea of what speed you’re aiming for.

The other method involves fishing the pattern more like a popper. This involves slightly longer, but much sharper strips than the above method. I find a few seconds pause between strips can trigger a strike using this method. Sometimes the strike comes on the first strip after a pause.

Finding a Mousing Area for Trout

Honestly, just fish where you would normally fish during the day. One key piece of advice is to have fished the water before in a daylight scenario. You want to identify any deep water, strong current, or snaggy areas that might cause you trouble in a low light scenario.

You’re not just looking for dangerous areas during your daytime scouting trip. You also want to identify any prime lies. Trout have a tendency to roam more at night, but many will still be hanging around the structure and current they use during the day.

Take special note of the above comment “trout have a tendency to roam more at night”. Yes, you still want to hit prime lies, but also try fishing water you wouldn’t normally fish during the day. Trout feel more secure in low light conditions. This does depend on the specific water you’re fishing, but trout will be much more likely to be prowling than holding a position like they do during the day.

What other gear to bring?

Aside from the standard fly fishing equipment, there are a few other essentials that you’re going to want to remember if you’re mousing at night.

• Bug spray – Even if the area has a mild mosquito population during the day, there’s a good chance the biting bugs will come out in force at night. Don’t forget the bug spray or you’ll be in for an uncomfortable night of fishing.
• Headlamp – This is the key piece of additional equipment needed when fishing for trout at night. It doesn’t need to be anything fancy, but it should have a low light and high light option. The following is a good headlamp and a modest price that will do the trick. Headlamp, 250 Lumens (Amazon Link)
  • Make sure you don’t shine the headlamp directly on the area you’re fishing, or you’ll spook the trout. I try to avoid using it whenever possible, but when I do use it I keep it the headlamp on the lowest setting possible. I will turn it on when landing and releasing a fish so I can see what I’m doing.
• First aid kit – Even if you’ve scouted the area during the day, the opportunity for injury is increased when wading and flinging a fly about in low light situations. Have equipment ready to deal with a hook up in the side of your head, or any nasty falls you might take.
• Bear Spray – This is quite situational, but is relevant if you’re in bear country. This is more due to the fact that it’s easier to accidentally startle one at night than them actively seeking you out. It’s not an issue in my area, but it should be a consideration in areas with a high bear population.

A few Notes on Personal Experience Mousing for Trout

I know most trout mousers spend their time chasing browns, and to a lesser extent rainbow trout. My experience is a bit different in that I primarily targeted big sea-run brookies and occasionally steelhead/rainbow trout (there was no brown trout in PEI).

Much like browns, brook trout have a relatively large mouth compared to rainbow trout. They had no problem fitting the fly in their mouth. Small brookies were not interested, but most trout caught mousing where in the 16-18″ range. These are big brookies by anyone’s standards. I, unfortunately, haven’t been able to get a 20″ plus brookie to commit to a mouse pattern yet.

I found shrew sized morrish mice were the most productive when targeting both the brookies and rainbows on PEI.