RIO's Pip Squeak

RIO Fly Designer Patrick Kilby


Photo by Arian Stevens

Mice were put on this planet to be food for all kinds of predators, from foxes to hawks to cats, and even to trout. Yup, plenty of trout eat mice, and many fly fishers take advantage of this with mouse-like patterns fished on a floating line for high-octane grabs from large fish. We tend to hear about “mousing” for trout mostly for nighttime brown trout on warm summer nights, or for Leopard Rainbows in Alaska and Russia drainages. There is no doubt that these are two areas you can have an amazing time fishing a mouse pattern, but let’s back up a second and explain what mousing is. Mousing is done with a mouse fly that floats. The fly is cast, typically with a 6 or 7 weight rod, then fished in long slow strips, or by wiggling the rod tip and collecting your slack line to keep the fly moving as if a real mouse was swimming. Or if in current, casting the fly across and let it swing on a tight line through likely areas. When fishing a mouse pattern, it’s important not to set the hook until you feel the weight of the fish otherwise, you’re more likely to pull it away from them. This is not an easy thing to do as it is an exhilarating moment when you see/hear your fly being attacked, and the natural reaction is to instantly set the hook. If you have ever watched ‘Shark Week” on the Discovery Channel, just picture your mouse as the fake seal being dragged behind the boat, and the shark is the trout. Bang! Out of nowhere comes this beast intent on devouring your fly with all the rage and power it can muster. Try keeping calm in those situations!


I don’t live near big brown trout fisheries, or in Alaska, so I tend to fish a mouse in situations that are more fitting. I prefer low light conditions like early mornings, or in the evenings, but I will also happily fish a mouse midday in full sun, or along shady grass banks or log jams. It’s more about my own curiosity. I’ve been tempted to see if I can only fish a mouse fly for an entire year. I have not done it yet, but I want to.

When I set out to design a mouse pattern, I had great models to look at first. In a previous life, I had worked with Jeff Hickman, creator of the Mr. Hankey and Ken Morrish, creator of the Morrish’s Mouse. These were the top two mice patterns out there, and both flies have been extensively fished and have piles of success stories.


Our friend Kate Crump sent me this note after she was able to help her friend celebrate her birthday in style.

“Thank you so much for those RIO’s Pip Squeaks. They came at the perfect time and we had so much fun. Those flies, time after time, perform so well and I have yet to have them hooked deep. The little pink on top makes it super easy to see and that is so helpful. Thanks so much. This was the first time she ever got anything on a mouse. The first fish tried to eat it three times and there was a lot of shrieking in my boat. She lost it and then this girl came up for it. She was a beautiful Perfect fish and Nicole was over the moon."

Let me start with what I loved about both. First, their natural colors and the use of a rabbit strip for a tail. The tail could swim freely and did not have hooks attached to it. I also love the size of both - slightly smaller than an actual field mouse, which makes them ideal for casting, and for fitting in a trout’s mouth.

When I designed RIO’s Pip Squeak, I opted to use a stinger hook, but attached with wire (not mono) so trout teeth would not damage it. I chose rabbit fur for the body, as this looks so realistic, but used a minimum amount so it would not be hard to cast when wet.

When mice swim their head is above water, so I tied this fly with foam at the front to help keep its head up, while the stinger hook design helps keep the back end down in the water, making it swim a lot more like the real thing.


A wet mouse is usually quite dark in color all over, except for their ears and back legs, which are generally an orangish/pinkish tone, so when designing this fly, I added two orange/pink rear legs, and shaped them to kick behind the fly like a real mouse. Most mice also have white chins or necks, so I tie the rabbit strip in a way that ensures the creamy white leather of the strip is underneath the pattern, and so that when wet, it looks like a white neck/chin area. Talking of rabbit strip, I only tie the strips in at the collar as this reduces material and hold very little water, but also covers the body perfectly with fur. For the ears, I matched the skin tone and shape. The cool thing is from underneath the fly you can only see the edges of the ears, but the angler, viewing the mouse from above, can see it a long way off, even in low light conditions.

As for the name, “pip squeaks” are usually picked on or bullied but as they find their courage, they learn how to stand up for themselves.

Fly shops all over the US carry RIO’s Pip Squeak, so if you want to try something new this season, tie one on and make your own version of Shark Week.


P.S. RIO has just launched a size 6 “RIO’s Pip Squeak Baby” which is fishable on 4 and 5 weight fly rods, and opens mousing up for 10” to 18” trout everywhere. If you’re like me and don’t live near big brown trout, or Alaska, give the baby version a try on your local trout stream.