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Top Trout Flies Course

Lesson 7 – The Rubberleg Stimulator

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The Rubberleg Stimulator

One of the Top 10 Trout Flies Ever Created

This fly, out of all flies for me personally, is my favorite confidence fly. I think when I was first learning I always had so much success and now after all my years of fishing and always searching for the next best new pattern, I still fish this guy as often as possible during the right seasonal months. While the rubberleg stimulator isn’t a year round success, it is so productive during the late spring into mid fall it warrants a spot on the list. It is nearly unsinkable, convinces fish from a distance to eat it, and is one of the easiest, maintenance free flies to throw during the day. Let’s learn a bit more about where this fly came from, when and how to fish it to maximize your success on the water. 

The Details

It’s a toss up on who invented the stimulator dry fly. Either Randall Kaufmann or Jim Slattery were the inventors, so for this purpose we’ll give them both credit. For all practical purposes, there were several other variations that were invented before the stimulator by other well known anglers, but they don’t attribute credit if it’s a variation. Regardless of authorship, It was designed to imitate a stonefly dry or a hopper and starting around run off and lasting into mid to late fall, the stimulator, or stoneflies for that matter, always are on the menu for trout. Most of us love steak, but we’d get sick of it if it was all we ate. Stimulators are the steak of the trout world and it almost always sounds good, unless you’ve had too much already. The seasonality on this fly and the size and colors used during each season is important to understand, so let’s review them now.

Graphs – Seasonality, Size and Color


The Secret to Why This Fly is So Productive

Despite all the talk in the past articles about how small bugs catch a lot of fish (which they do), there are some large bugs out there.  Salmonflies as nymphs get as big as 3 inches long before they begin to hatch into adults, cranefly larva can be up to 3 inches long as well.  As adult insects, these flies remain large.  Then you have terrestrial insects like beetles, hoppers, cicadas, moths, and more that are all a very active part of rivers.  Though many of these insects don’t hatch out of water, they spend a lot of time near water either in the trees, grasses or the riparian environments around the rivers we fish.  At the right times and under the right conditions these bugs can be the primary food source for trout.  A rubberleg stimulator is a great, all purpose big bug imitation and while it most accurately looks like a golden stone or salmonfly, it is a close imitation of a half a dozen other bugs such as hoppers, moths, cicadas and beetles.  It’s insect profile and ability to look like so many of these large bugs creates a reaction strike from most trout.  I don’t get many fish on this fly who sip it gingerly as you would a midge.  It’s often a slap and a splash and the fly is under the water or the fish flies out of the water 2 or 3 feet and my fly is carried with it.  Trout eat this fly with tenacity because it looks a lot like everything and they don’t want to pass up a big meal.

In addition to that, trout know the difference between a midge, that doesn’t leave the water with much urgency vs a moth who accidentally landed on the water and is trying quickly to get off the water so he isn’t trout food.  This urgency makes a rubberleg stimi something trout will eat quickly.  They instinctevly know they don’t have a lot of time to react, so they eat first and think later.  This works out great, as you can imagine, for the angler and is why this fly is so productive.

In summary, it looks like a lot of big bugs and trout react very quickly to this pattern due to the nature of what it imitates making it a very productive fly.  Let’s learn now a little more behind the entomology of these insects it imitates and learn about some of the least understood insects in the fly fishing world.


The Entomology Knowledge on This Fly

Golden Stonefly | Stonefly Dry
Sizes: #6 – #12 | Colors: Yellow, Tan | Seasons: Early Summer to Fall

A golden stonefly is a common stonefly found in many rivers, but gets less fame since the salmonfly is bigger and often has thicker hatches.  I don’t come across many golden stonefly hatches as much as I simply see them around from early summer to mid fall.  It appears they hatch sporadically throughout the entire season vs in big bunches.  This is somewhat true with all stoneflies.  There are times for hatches in large numbers, but there is a big opportunity to throw these patterns anytime, because there are active insects in the water all summer.  A yellow or tan rubberleg stimulator is an excellent color option for golden stones and no modifications are needed to match this insect.


Salmonfly | Stonefly Dry
Sizes: #4 – #10 | Colors: Brown, Black, Orange | Seasons: Early Summer to Fall

Salmonflies get a lot of fame for good reason.  We all love fishing big dry flies, and it doesn’t get much bigger than the salmonfly.  There are huge hatches out west of these on rivers like the Deschuttes, Conejos, and Gunnison.  Typically more of a western bug, they are found in a lot of rivers but just not the same size as these giants.  There are many smaller salmonflies that hatch in small creeks and streams and using a size #10 or #12 in black, brown or orange will bring the fish to the surface.  If you have 2x or 3x long hooks like a TMC 200R, they are the best for tying these flies. I like to use a heavy hook to make sure they sit facing up the right way instead of a direct dry fly hook which sometimes isn’t enough to get the fly to turn over right with all the material on the fly.  I like to tie a black body with an orange head to them as my favorite salmonfly imitation.


Yellow Sally | Stonefly Dry
Sizes: #12 – #18| Colors: Yellow, Tan | Seasons: Mid Summer to Fall

Yellow sallies get mistaken for all sorts of insects, most often PMD mayflies.  They hatch during the same time, but the difference is visible if you know what to look for.  The yellow sallies, as all stonefly dries have, fly with 2 sets of wings and resemble a helicopter in the way they fly.  Mayflies are faster up and down, up and down type of flight pattern, while stoneflies are more hover and move gracefully in a direction.  Their wings lay down over their backs like the stimi fly pattern imitates instead of wings straight up.  Have some smaller stimulators in yellow and tan in order to imitate these accurately.


Spruce Moths & Other Moths | Terrestrials
Sizes: #12 – #16 | Colors: White, Tan | Seasons: Mid Summer to Fall

Moths are often overlooked because they don’t hatch on the water or anything.  I find this funny cause we give a ton of importance to hoppers which are just the same, but moths are often overlooked.  There are few hatches or times of year where moths are hatch-worthy and should be directly imitated, but I have seen dozens and dozens of moths over the years land or fall onto the water only to be eaten by a trout moments later.  It’s big, winged and looks like an insect, a hungry trout does not discriminate.  A tan rubberlegged stimulator is a great imitation for a moth as well as other insects, so it’s just a good color to have.  Top colors overall for a stimi are probably yellow, tan and black in my experience, though many other colors produce well.


Hoppers | Terrestrials
Sizes: #6 – #14 | Colors: Yellow, Tan, Green, Pink, Red, Orange | Seasons: Mid Summer to Fall

Everyone loves big fish on big dry flies.  Windy days where a lot of grasses sit next to streams can knock hoppers into the water getting the trout to keep one eye focused on this kind of behavior.  This is where a rubberlegged stimulator works so well.  Whether the trout think its a stonefly recently hatched, a moth, or a hopper, it’s large and it hit the water during the summer months.  Trout will often not refuse a meal of this size if they are actively feeding.  There is much debate on the best colors and while tan, yellow and green are great colors, there is a lot of hoppers showing up these days in pink, orange and red.  At this point, it is more of an attractor color, but they do produce some fish from my experience are may make the difference when trout are used to refusing a stimulator in standard colors.


Cicadas | Terrestrials
Sizes: #8 – #12 | Colors: Green, Brown | Seasons: Mid Summer to Fall

Cicadas are the enigma of the insect world.  They hatch on 13 and 17 yr cycles buried deep in the ground below trees.  When they hatch, they time the hatch in excessive numbers and use this over population as a defense against everything that eats them.  To be clear, everything eats them.  I’ve seen trout, carp, bass and walleye even come up and pick these off the surface when they hatch.  They don’t hatch every year since they are on those cycles, but there is more than one brood in the ground and usually its every 2- 5 years you see a pretty good hatch of them.  You’ll hear them in the trees making noisy and rhythmic humming.  Often mistaken for grasshoppers, cicadas make this sound while they looking for a mate.  The sound can be very loud when in large numbers as they commonly are but it reminds us all of summer.  Olive, green and brown rubberleg stimulators are great imitations of these insects.  When the hatch is on, the fish go nuts on these guys and it is a staple for big fish.

Identify the Signals the River Provides to Learn When to Fish It

There are a few signals the river provides that helps us know when throwing a rubberleg stimulator will likely work, but let’s be clear,  from Mid-May to October, there isn’t a bad time to throw one of these on unless you see fish eating something like caddis or mayflies actively.  It makes for a great search pattern during any time of the day.  Let’s look at a few signals the river provides:

When you see stoneflies in the air and fish are sporadically rising

Trout will sit in feeding lanes when eating midges and mayflies, but caddis and stoneflies are all over the river most times and trout are sitting, watching, waiting for them to land for enough time to come up and eat them. When you see a few of these flying around, but only see sporadic rises in several different spots along the river, this is usually a good sign fish are eating stoneflies. Cover any water you think may hold a trout below and don’t be afraid to dead drift and twitch this fly. Stoneflies rarely hold still while on the water. They are either their depositing eggs or there on accident trying to get situated to get off the water before they are eaten.

High Water is Stonefly Time

Many stonefly hatches occur as run off peaks. I assume they do this to help increase survival rates, but it often means as anglers who take time off fishing during run off, miss some big insect hatches. Just before or after run off is still a good time to catch the hatch however, so keep an eye out for high water season and get your big flies out and ready.

When Fish are Rising to No Apparent Hatch

Sometimes trout are eating anything off the surface they can, even when there is no active hatch. When you are seeing some periodic rises, but nothing is hatching that you can see, a rubberleg stimulator is a great fly to try. I like to do a dry dropper in this situation so no cast gets unused maximizing the chance for them to eat my dry, or refuse and then take my dropper.

Aside from those signals above, there aren’t a ton of signals you’re going to see on the river. That’s ok though, because this really is a use anytime kind of a pattern, so have them in sizes #8 – #14 in yellow, tan and olive in your box and try them out often. Let’s learn about a few different ways to present the rubberleg stimulator.


Presentation Tips on the Fly

The Rubberleg Stimulator is one of the easiest flies to fish. It floats high and dry, is very easy to see and yet at the same time isn’t so large or bulky that you struggle fishing it with a breeze. It fishes well in tandem with other flies or by itself if you are working the banks and need to get close. Let’s go over a few of the best ways to present this fly now.

The Double Dry Set Up

This is my favorite way to fish a RLS (Rubberleg Stimulator) in the summer a I love dry fly fishing. I like to fish this as the first fly in a two fly set up and then trail a parachute adams, smokejumper or elk hair caddis behind it. This functions just like a dry dropper would often getting the fish to come up for both, but if they refuse the larger fly, they still eat the smaller fly while they are up there. I space out the flies at least 24 inches apart as you don’t want the current dragging one fly over the other. 36 inches apart is probably about the max, because beyond that it is hard to get the last fly to turn over properly and it can make it hard to set the hook if it takes the last fly as well. 18 – 36 is the range I’d recommend with 24 inches being about the right distance most days.

The Dry Dropper Set Up

The RLS is perfect for a dry dropper set up when you want to fish a heavier fly below. Often, you can’t throw a size #12 tungsten copper john below a parachute adams without drowning that adams after 3 seconds into the drift. This gets annoying because that parachute adams goes under and it’s hard to tell if a fish ate or your nymph just sunk as intended. A RBL is big and high floating enough to hold up some pretty heavy flies and if you are wanting to go really heavy, tie some foam under the wing along the body and the thing becomes unsinkable unless a fish drags it under, in which case you win! It depends on the depth of the river and where you’re fishing but I typically stay in the 18 inch to 48 inch dropper distance. 48 gets tough to throw but when fishing deeper holes it can help to have that depth if they aren’t coming up for your dry. Past 36 inches however, you should probably just be nymphing so keep that in mind and just switch the rig. I fish tippet rings alot and with a RBL, the tippet ring doesn’t mess up the drift at all, so I find it pretty easy to switch from a RLS and dropper to a nymph rig without much tying or trouble on the river, especially when you pre rig a set up.

The Bank Sniper

If you are fishing the RLS to imitate a hopper, it can really help to get 3 inches or closer to the bank. If you are fishing any two flies in tandem, it’s hard to not land one fly on the bank and one in the water when you snipe the banks like this. I find it’s better to just go with a single dry fly. It’s simple and you can really get close to the bank where the trout are waiting for this fly. Practice makes perfect in learning to hit the banks tightly, but it’s a worthy aspiration to practice and when fishing from a float boat, it’s super fun working the banks with this fly all day often finding double digits by the end of the day landed to the net.

Getting Twitchy With It

We mentioned this earlier, but stoneflies, hoppers, cicadas and moths all are not meant to be on the water. Aside from female stoneflies depositing eggs, they don’t sit on the water’s surface if they don’t have to because they know they get eaten too quickly being that big of a target. Trout can often see these big bugs flying around before they even hit the water and all that motion gets them all jazzed and ready to eat. When your fly does hit the water, a dead drift will work well often, but don’t be afraid to try a little twitch or wiggle when you can make it happen. Subtle is key, you’re not popping a bass plug on the surface, you’re making small little movements and wiggles on the fly. This can get the fish excited as at times all they are looking for is something moving and they assume food. Keep this little trick in your back pocket and use it every 3-4 casts if a dead drift didn’t produce on the casts or areas you thought it would.


Common Variations and Ways to Modify the Pattern for Success

There are a ton of variations around the rubberleg stimulator. The RLS itself is a variation on the stimulator and I like legs on the fly more often than not which is why I made the rubberleg version the top 10. Let’s go over all the different modifications you can make on the fly, then highlight several of the top variations that are out there.

It’s actually better to call these modifications, additions instead because you can’t really change too much on the pattern to change things, but adding some additional materials or changing the style of the head can make for a worthy variation:

  • Adding to the Body:  You can add dubbing of all colors and kinds changing the color of the body as much as you’d like.  In addition, adding some foam to the top of the body makes it more buoyant and gives it a wider, stiffer profile that resembles terrestrials like cicadas and hoppers more accurately as well as keeps it from sinking.
  • Adding to the Wing:  A lot of people add white calf hair and some krystal flash to the wing.  I like this as it adds additional buoyancy and visibility to the fly both for the trout and for the angler.  You an also add a CDC underwing to help it float well and give a more general wing profile as the CDC diffuses the prominent overset wing that makes it look like a stonefly.  I like a CDC underwing if I’m imitating a moth or generic insect that has landed on the surface.
  • Adapting the Head Style:  The most common changes to the head are adding a parachute style head to the fly like seen in the PMX below, or using the deer or elk hair to create a buoyant head as shown in the madam X below as well.  Parachute flies float well as they create surface tension on the water which doesn’t break as easily as it would without the parachute post.  It also makes it easier to see and you can add white, pink, orange, green or any color needed for you to see it on the water.  I like doing a PMX with a foam back and a pink or orange parachute post if fishing really fast or high water.  It is impossible to sink and is easy to see which is very helpful in fast water.

In additon to those modifications and additions, here are some popular variations:

Madam X

Great for imitating stoneflies and hoppers, the madam X has a simple, low wing profile and floats lower in the water, but floats well all the same.


The PMX is a parachute madam X and floats higher in the water and is very buoyant and one of my favorite options when fishing it as a dry dropper.

Sofa Pillow

The sofa pillow is a thicker version of the fly without legs and is extremely buoyant and used for fast and broekn water fishing presentations


Meet the unsinkable foamulator. These can practically be used as a personal floatation device in emergencies, and even the heaviest of nymphs can ride under these as a dry dropper. When trout are on the edges eating stonefly nymphs crawling out on the banks as they emerge, the foamulator covers the hatch and the pseudo “emergence” of stoneflies well because you can put a large stonefly under these without sinking the pattern and can catch a lot on the nymph and the dry.

Yellow Sally Stimulator

Tied sparse and small, the Yellow Sally Stimulator is great for yellow sallies and smaller stoneflies. This is a good time to share this tip. Early on in the year, fish like bigger simulators, but as each month goes on, they seem to like them smaller and smaller. So fishing a size #8 in May, #10 in June, #12 in July, #14 in August and #16 in September seems to be a good rule of thumb. The yellow sally stimulator is good for those #14 – #18 applications as a regular rubberleg stimulator can be tough to tie in smaller sizes.

Standard Stimulator

Same fly, just no legs. Great pattern as well, I think if trout are on a stonefly exclusively, a stimulator is a better fly, but if fish are looking for all sorts of bugs, a rubberleg stimulator will often out produce.

Enjoy the image gallery of rubberleg stimulators and variations below and we hope you have a strong knowledge of this fly and how to use it and why it is successful. Many anglers fish this fly with success, but don’t understand why, and now with this knowledge you can know when and why to fish it vs just guessing which will increase the amount of fish you catch over time. Let’s get into lesson 8 now, learning about the top producing caddis dry fly everyone is sure to know.

Image Gallery of Variations and Colors of the Fly

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Read Introduction Here

Read THE BASICS Lesson

Lesson 1
Lesson 6
Lesson 2
Lesson 7
Lesson 3
Lesson 8
Lesson 4
Lesson 9
Lesson 5
Lesson 10

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