It’s funny how a few questions can lead to a deep conversation about the simplest of devices. Paul, (The “Professor”) and I were nymphing a stretch of creek and I found myself focusing on his strike indicator. So, I asked Paul about his indicator and what type he likes to use. That simple question prompted an inquiry on “why use strike indicators fly fishing?”.
Why use strike indicators when fly fishing? Strike indicators help us detect strikes (0bviously), can help maintain your fly at a certain depth level, assist with monitoring line movement and calculating drift speed, and aid by adding additional reach.
As Paul and I compared notes we discovered we both use strike indicators as an additional tool to aid in strike detection. Like any tool, it needs to be the right one to fit the job at hand. Our conversation defined for us what the basic uses of strike indicators are. That helped us to decide when to use an indicator and which type was best for the given situation. Lastly, like any tool, we had to learn how to use it or in this case, how to fish a strike indicator effectively.
At the conclusion of our discussion though, we found ourselves laughing out loud at each other. A strike indicator is the simplest thing, and yet, our conversation turned it into the most complicated thing. Seems the more a person fly fishes for trout, the more complicated the simplest of things can become. But hey, that’s the fun of being a fly fisherman. So, let’s examine the little tool we call a “strike indicator” and explore “why use strike indicators when fly fishing”.
What is a Strike Indicator?
There is no escaping a simple truth and that is, although strike indicators are typically smaller, lighter, and made from different materials, they accomplish the same thing as a bobber. But, because we are fly fishermen we can’t use the term “bobber”. I mean bobbers are for little kids throwing bait, right? So, we call our “bobber” a “strike indicator”. Sounds impressive, doesn’t it? It seems fitting that a strike indicator needs to become a sophisticated and complicated tool. This is fly fishing we are talking about here. It stands to reason then, that the strike indicator must be “designed and engineered” to fit into our complicated fly fishing world.
Ok, Ok, all sarcastic kidding aside. Simply put, a strike indicator is a floating object that you attach to the leader of your fly line. It is primarily used to help detect a strike. It is similar to a bobber, but it is made of different materials specifically designed for use in fly fishing. The indicator itself is often brightly colored giving the fly guy a visual to concentrate on. Any variation in the movement of the indicator as it floats down the stream signals a possible take.
Strike indicators are made using anything that floats from foam, yarn, wool, or plastic. I know some guys who simply tie a piece of yarn on their line while others attach a nymph to a dry fly and use the dry fly as the indicator. I can remember years ago using a toothpick tied to my leader simply because they were cheap and losing one didn’t matter, and, yes they worked.
What Are the Different Types of Strike Indicators?
When new to fly fishing, especially nymph fishing, the use of a strike indicator is a big help in detecting strikes. There is a variety of indicators to choose from and like anything, it takes trying a few to find the one(s) you like and perform the best for your individual needs.
Types of Strike Indicators
Foam Football Strike indicators 
These indicators come in an array of sizes and colors. They float high on the water and are easy to put on and remove from your leader. They slide onto your leader and when removed won’t leave any kinks in your line, which is nice.
Balloon type.
These are small plastic balloons in a sense, that you attach to your leader. One has a grommet you put your leader through or attach using a toothpick while the other clamps onto your leader. Again they come in an array of colors and sizes.
Thing-a-ma-bobber
Air Lock
Wool or Yarn Indicators
These are made from a tuft of wool or yarn. They are extremely light, highly visible, and good for use in shallow water over spooky trout.
Stick on Indicators
These foam indicators fold over your leader and stick together. They are designed for one-time use.
Dry Fly
Although not considered an indicator Dry flies can be used as an indicator. Attaching a nymph to a dry fly lets you cover both fishing the surface as well as below the surface.
Why Use A Strike Indicator for Detection?
I mentioned above that Paul and I use strike indicators for more than just strike detection and I’ll explain that in a second. But first, let’s talk about detection. Remember that nasty word we’re not supposed to use, you know “bobber”. When bobber fishing, if the bobber bounces or submerges, grab the pole and set the hook. Although strike indicators are similar to bobbers, they don’t necessarily act the same way.
Strike indicators for fly fishing are made of the lightest materials in order to float on the water’s surface. As they float down the stream any change in the way they are floating is what an angler should be looking for. But, I think many anglers are waiting to see the indicator get pulled below the surface and the truth is, this rarely happens. Trout can pick up and reject a nymph in a matter of seconds and many times these pickups go completely undetected.
Instead of waiting for the indicator to be pulled under, watching the indicator for any slight change in movement is what should be happening. A slight bump, hesitation, or stop means to set the hook. (And setting the hook is as simple as lifting the rod tip a bit. It doesn’t take more than that.)
The Subtlety of the Drift
“Subtle” is a word I use a lot when talking about fly fishing. Everything in fly fishing seems to be a “subtle” difference. I have fished a size 12 nymph only to change to a 16 and the catch rate went up dramatically. Subtle difference I know, but it made the difference.
“Subtle” applies greatly when using strike indicators. There is a rhythm to the float as the indicator conforms to the flow of the stream and “becomes one” with the current. As it floats on the surface it can become almost mesmerizing as you concentrate on it. The anticipation of a strike has a built-in drama all its own as well while waiting for the slightest divergence from the rhythm.
That said, any change in this rhythm means something. Maybe it’s a touch of the bottom or a submerged twig or the biggest trout of your life. It’s a subtle difference and the best nymph fisherman has learned how to pay close attention to the “subtlety” in the float of the indicator.
Quick Word About Drag
Drag is the unnatural movement of a dry fly or nymph when compared to the current. Drag is the fly guy’s worst nightmare and trying to eliminate drag is a constant battle he faces whether nymph fishing or dry fly fishing. Indicators serve another particularly important purpose in that they can help reveal drag.
When watching the indicator, does it match the speed of bubbles or debris floating on the surface? If so, chances are pretty good you have a drag-free drift going. If not, then something needs to be adjusted. My Simple Approach to Nymph Fishing
Calculating Drift Speed
Another reason why we use strike indicators when fly fishing is to help in calculating drift speed. Any advantage you can add or gain to your skillset is a good thing. By using the indicator to calculate drift speed is another aspect of an indicator as a tool. The current or flow of the creek is a bit more complicated than we think in most cases. Stationary objects in the water change the speed of the current as water is forced to flow around them. The speed of the current is also altered depending on the width and/or depth of the stream at any given point.
The strike indicator, as it floats along, will give you some clues as to how fast a section of the stream’s current is flowing compared to another section. Faster current needs to be handled differently than slower current. Faster current may require additional weight to get down into the strike zone quickly. Sometimes moving a few feet upstream is necessary to attain a drag-free drift. Whether it is adding additional weight, moving a bit farther upstream, or both, watching the speed of the indicator will let you know what is needed.
How to Tell If The Nymph Is Deep Enough
Additionally, water depth also plays an important role in the flow of the current. Water near the riverbed flows slower than the surface water. As I mentioned, objects on the bottom have an effect on the current. Rocks, weeds, debris, tree limbs, roots, all tend to slow the flow near the bottom. And guess who is resting near the bottom. Trout like “edges” between faster and slower water. They’ll position in slower water to conserve energy but close to faster current to pick off food traveling in the faster current.
The challenge of fishing deeper water is knowing if you’re near the bottom while maintaining a drag-free drift. Strike indicators can help you determine the drift speed and depth, but you need to pay very close attention to the indicator. Studying the strike indicator to determine if it is moving slightly slower than the surface current is the clue. If it is you are most likely near the bottom. When your nymph(s) and weight float in this slower current, they will slow down the speed of your strike indicator on the surface. It’s a subtle difference so pay close attention. How to Read a Trout Stream to Catch More Trout
Monitoring line Movement Using an Indicator
Additionally, another reason, as to Why use strike indicators when fly fishing is to track the movement of the fly line at times. Wet fly fishing is an effective form of fishing and catches a lot of trout. The art of wet fly fishing is casting across and downstream to have your fly drift with the current but cut across the stream at the same time. This technique is called “swing”. Wet fly fishing is all about “swing”. Learn: The Simple Truth To Fishing Wet Flies
Swing is casting across and downstream then mending the line as to put a bow in your line. As the line travels downstream the bow begins to straighten out as it comes across and downstream. When the line reaches the point where it is almost straight downstream below the angler is often when the strike occurs.
I have this trick I use from time to time when fishing wet flies. It involves using a balloon-type indicator and some weight. (I’ll explain using balloon-type indicators in the next section.) Using just enough weight to pull the fly down but without pulling the indicator below the surface to suspend the fly and maintain a certain depth. The idea behind this is to mimic an emerger coming up from the bottom and struggling to the surface.
Using the same cast and presentation, I watch the indicator as it travels along with the swing of my line. This helps me gauge where my fly is and how far away from me it is by monitoring my line. Primarily the indicator is helping me gauge the distance to an area. By using the indicator, I get a better feel for how far my cast needs to be to get the fly into a given area.
Maintaining a Certain Depth Level
I use two types of strike indicators regularly. The football type is my normal go-to indicator. These indicator types are constructed using a Styrofoam-like material making them extremely lightweight. I like to use the smallest ones I can find. What I like about this indicator is its ability to submerge yet still be an effective indicator.
Creeks have various depression in the riverbed. Sometimes these are deep but not very long, just a few feet. Most objects drifting along a creek bottom will naturally fall into a depression as they drift and rise up out of the depression maintaining the same distance from the bottom as the water flow pushes them along.
When my weight and nymph fall into a depression they pull the indicator down along with them. For the small distance it travels to get through the depression I can still see the indicator as it travels just below the water’s surface. I can’t tell you how often I have caught trout with a submerged indicator.
The other type of indicator is the balloon-type but I use these for a different purpose than the football type. Better known by their trade names, the “Thing-a-ma-bobber” or “Airlock” are constructed from plastic with trapped air inside. Personally, I like the Airlock style because they don’t kink my leader and are easily adjusted up or down the leader. But for my purpose, either one is a good choice.
Suspending a Fly
What I found using these is their ability to suspend a heavier fly from them. Holding a fly or better said, suspending a fly in the water column beneath one of these indicators can be magic at times. Here in Pa., this is a highly effective technique especially from April-ish to June.
Finding the right amount of weight for the size of the indicator is the trick. You need just enough to let the indicator float normally while helping pull the fly down suspending it below the indicator. Weighted flies are a big help for this but, you may still need to add some weight up from the fly.
When trout are feeding in the water column this is a great way to fool them. The cool thing is adjusting the length from the indicator to the fly up and down. This positions the fly at different depths while maintaining a certain depth level as it drifts through the strike zone of the trout. This tactic lets you probe through an area several times to take advantage of suspended trout.
Adding Additional Reach
For the most part, when it comes to drifting nymphs, short casts and keeping a tight line is the key to successful nymph fishing. A tight line provides a “feel” and along with a strike indicator’s visual, is how we can detect a strike. The trick to tight-lining is keeping the fly line itself off the water and maintaining a straight (tight line) leader between the fly line down to the nymph. Obviously, more easily said than done but it is what a good nymph fisherman strives for and once achieved increases his success.
But there are always exceptions and one exception is additional reach. For example, a longer cast and father distance naturally places fly line on the water and this is typically not good. This generally causes drag and in addition, takes away “feel” as the heavier line needs more energy to move it.
For times when casting to an area requires a little more “reach”, using an indicator can help. The added distance means more line out, and of course, more fly line on the water. An indicator then becomes the main detection device. Along with watching the indicator is trying to keep the fly line traveling at the same speed as the indicator. This is a balancing act you need to have for a drag-free drift.
Typically, casting a nymph a long way isn’t a productive endeavor in most cases. But sometimes you have no choice. It’s another reason though, why using strike indicators while fly fishing can be helpful. In this case for the purpose of monitoring your fly line to keep it drifting at the same speed as the indicator.
Dry Flies
The last “indicator” to mention is a dry fly. It’s not an indicator by definition but certainly can work like one. The best part of this is the fact that a dry fly has a hook, of course, so you have just doubled up on the opportunity of a trout taking your “indicator” along with your nymph.
If you go this route you’ll need to use a pretty buoyant dry fly to keep the nymph from pulling it down. Stimulators, foam beetles, Parachute Adams, or a Royal wolf are examples of possible flies. But realistically use whatever dry fly you want as long as it can stay above the water.
The ideal setup is to match the hatch with both your indicator and nymph. If you see cadis are rising maybe a caddis emerger and an Elk hair caddis for the indicator may be the ticket. This is one of those “experiment and see” situations that makes fly fishing so much fun. Play around with different things and who knows what you may come up with.
Line Placement
When one asks the question “why use strike indicators when fly fishing”, the next natural question is “where should I place my indicator”? There is a rule of thumb that says your indicator should be one and a half times the water depth up your leader from the fly. Now I don’t know about you, but guessing the water depth without walking out into the middle of the stream to gauge it becomes pretty tough.
So, I start out by placing my indicator about two feet down from my fly line on a 9ft leader and adjusting from there. My goal is to have my nymph touching the bottom from time to time on a drift without getting hung up. But, that said, if you’re not getting hung up you’re not down far enough. Nice catch 22 right? My advice is to adjust the indicator often. As you wade your way up or downstream, the creek depth is constantly changing, so should your indicator.
One last thing to consider is color. Not so much for the trout but instead for you. Let’s face it, if you can’t see the indicator then it won’t do you any good to use one. White is a good choice in that many of the bubbles and foam on a stream are whitish and it will blend. The football type I use is white and red and my “Airlocks” are several colors. I’m not worried about fish seeing it although there are times where I need to be a little more cautious.
Conclusion
Why use strike indicators when fly fishing? Like any tool we use there are a time and a place when they are most effective. Strike indicators are a great thing for new fly guys to use as were training wheels on the first bike we rode. Over time I would not be surprised that as you gain more experience in nymphing the indicator goes away. Some of the best and oldest fly guys I know will still use an indicator from time to time and why not? The reason we fly fish is to catch fish, right? But remember, it’s called a strike indicator, whatever you do, don’t call it a bobber. Fish on!
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Related Questions
Do you use a strike indicator with dry flies?
Do you need a strike indicator fly fishing?
