Mop Fly Thoughts, and a Tutorial

by | Jan 17, 2018 | 9 comments

“It’s Mop Fly mania, I guess.”

That’s how a fishing buddy described it in a text, along with a link he sent to another Mop Fly article. When the Wall Street Journal writes about a fly pattern, you know the fly has made it to the big show. Now, smart fly shops are even making the trip down the cleaning-supplies-aisle of the local hardware store for you. The mop strands are clipped from the mop head, bagged up and sold as fly tying materials. And good for the fly shops. I bought my own mop pieces from a fly shop and was happy for the convenience.

Full disclosure, here: the Mop is not one of my go-to flies. Far from it, really. Admittedly, it’s hard to break into the top of my lineup. I work in a few pinch-hitters now and again, but if they don’t come up with a home run within a few at bats, I send them back to the bench, to the shadowy corners of my nymph box with fading hopes and bleak futures.

But I’ll be damned if the Mop Fly doesn’t catch trout from time to time. And I know anglers who are fanatical about the Mop fly. Somebody out there even has a Mop Fly tattoo — you know who you are, dude.

So I’d be remiss if I ignored the ongoing conversation.

A few thoughts

I think the chartreuse version of the Mop fly is pretty much a Green Weenie. Basically, when a trout takes something that big and green, I think the trigger is the color and not necessarily the way the material is tied to the hook — maybe. That’s right, maybe. I give this Green Weenie comparison with plenty of caution. It’s important to realize that the GW can be tied a few different ways (small, large, beaded, weighted or not, with rayon chenille or other). I carry Green Weenie’s in two versions, and one of those (rayon, beaded and weighted) is damn close in appearance to a chartreuse Mop. It’s one of my high-confidence flies, and like I said, the top of my lineup is pretty much set.

But some trusted friends insisted that I was missing something big by not fishing a Mop, so I decided to get on board. I’ve fished the green one, but I’ve given much more time to the tan version of the Mop Fly — and I’ve caught fish.

The Mop is different, and I like it — especially the way it hugs the river bottom. I have other flies that do similar things, though. I often like to overweight my point fly, and the Mop is a great fly for doing that.

READ: Over or Under? Your best bet on weight | Troutbitten

I have a lot of history with heavy point flies. I end up going through cycles of nymphing, where for weeks or months at a time, I enjoy fishing with heavy point flies, believing that the extra control over fly placement and fly speed provided by heavy weight is a huge benefit. Then a few months later I find that I’ve switched over again to mainly fishing much lighter flies, believing that light nymphs drift more naturally. Both methods certainly catch fish.

All of this is good subject matter for another article, but I’ll stay on target here. Suffice it to say the best solution is having both tactics at the ready, then vary them to suit water conditions and the moods of testy trout.

I use the Mop Fly almost exclusively as a heavy point nymph. I tie it with enough weight to get down quickly, to overcome the built in material resistance and to plummet through the water column. I like how it stays down, yet hangs up less than some other flies. It’s just different. Polish Woven nymphs are another of my favorite heavy point flies, but they’re not the same — I feel the bottom more with Polish Wovens, and they don’t glide as much as the Mop does. Isn’t it wonderful to have all these options?

So I’m no longer a Mop fly virgin. I’ve been fishing them on and off for a year or so, I guess. And I’ve discovered some of my own preferences; I’ve realized some tendencies, weaknesses and strengths, of the Mop Fly. On the scene for many years now, the Mop is a fly that I’m having fun working into my own lineup.

READ: What Moves a Trout to the Fly | Troutbitten

Olsen says it

I recently came across Devin Olsen’s tutorial on the Mop Fly, and as usual, Devin’s scientific thinking comes through in his writing. In the article, Devin (of Tactical Fly Fisher) points out how the Mop changes the way a second nymph fishes too, and sometimes just swapping one fly out for a Mop causes more eats on the second fly in the rig. Nice. Great point.

Devin writes the following:

So what changed? I thought about the situation for a while and I realized the Mop was changing the way my rig drifted.

Because the Mop has a lot of volume and mass (much of it water weight), once it has reached the slow boundary layer near the bed of the river it takes a lot more force to get it to leave that zone than other flies.

That’s a precise explanation for what most Mop fishers have also experienced, and for how I personally like to fish the Mop fly.

Devin has a good video for the Mop Fly too. I tie mine on scud hooks with tungsten beads and lead wraps. Tied this way, most flies ride inverted. You don’t need the jig hook.

Rhyacophila. Photo from

One last thing: I guess the Mop Fly gets some grief because it’s not constructed from “traditional materials.” It’s considered a junk fly because it may not look like anything trout are used to eating (sure it does), and it’s often tied in gaudy colors.

This argument is counter-intuitive to me. If a fish eats it, fish it. Fly fishing’s original sin is added weight, anyway. So either fish with no weight ever, or don’t get bitchy about what nymphs look like. Or . . . draw your own lines, but maybe don’t be mean to anyone else about their’s.

Be happy. Be fishy. Have fun.

Enjoy the day
Domenick Swentosky

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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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  1. Love the Mop. I agree, though. It’s not a miracle fly. Guess nothing is. Green Weenies are great too and I like tying them on short shank hooks to let a longer tail hang off the back.

    Thanks for the blog! Love the site.

    • I like longer tails on GWs too. Cheers. I’m glad you enjoy the site.

  2. The MOP! I know it’s gotten a lot of press, but I’ll fish the Mop any day of the week. I keep it in the front of my rotation.

  3. Do you use pink or any other mop colors? What sizes do you think work best?

  4. I have a bunch of these and still haven’t fished them yet. They’ve been the craze for the last couple years.

  5. I just fished the mop fly for the first time during the PA Trout opener. I was armed with more realistic patterns which, according to the hatch guides, were THE must-have flies (e.g. yellow stones, caddis emergers). I had zero activity until I tied on a huge, ridiculous mop. I hooked up on my first drift and I kept hooking up. I doubt it will catch fish like that every day or every place, but it has earned it’s way into a prominent position in my fly box.

  6. The Mopp is King of the creek. I have caught more fish on it than any other fly the last two years. I feel bad fishing it because I swear you could use it on an ultralight but that said I seen brownies move three feet to eat them and they hit them hard. It is almost cheating…

    • Hey Beau,

      Man, I never feel bad about using any fly. If trout eat it, I’ll fish it. I’ve said here before, I’d still fish bait if I thought it worked better.

      Presentation is the real King, in my opinion. And I daresay the WAY you fish Mop flies is the real key to your success with them. That explains why the next guy doesn’t do very well with a mop, and why the Green Weenie is a killer pattern for me from late spring to late fall, but I have friends who can’t buy a trout on them. I know we all think we are out there trying for a dead drift on all of our nymphs, but let’s be realistic about what we are actually doing, especially on a tight line. We have a lot of influence over the flies. And as I wrote above, I think the way the Mop hugs the the bottom of the strike zone makes it pretty unique. And you happen to be excellent at making that work.

      Know what I mean?


  7. Excited to try mop flies! Love your blog and I am not a blog reader but you have outstanding content of interest to me. Exactly what I want to read. Thank you.


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Domenick Swentosky

Central Pennsylvania

Hi. I’m a father of two young boys, a husband, author, fly fishing guide and a musician. I fish for wild brown trout in the cool limestone waters of Central Pennsylvania year round. This is my home, and I love it. Friends. Family. And the river.

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