How to Use a Strike Indicator Fly Fishing: Expert Tips

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A strike indicator helps to tell when a fish has taken your nymph allowing you to strike before the fish has spat out the fly.

Fly fishing purists might turn up their noses, but strike indicators help anglers spot subtle bites (as well as the more obvious strikes) and land more fish when they are nymph fishing.

In this article, we break down what makes a good strike indicator, how to use a strike indicator effectively when you are fly fishing, and in what situations they are most helpful.

What is a strike indicator?

A strike indicator is anything attached to your leader between the end of the fly line and the fly itself that is colorful and you can follow with your eye as your nymph drifts down the stream.

What Types of Strike Indicators Are There?

There are many different types of strike indicators you can use while fly fishing, which we have explained below.

Bobber-style strike indicators

There are the round or oval airtight ball-shaped indicators that you attach to your line with a little rubber pin. The advantage of this type is very high buoyancy and visibility (you can see them even in foamy pocket water) and that you can adjust the distance from the fly easily. The main disadvantage when fly fishing with this type of indicator is they tend to hit the water with a decent old splash and can spook wary trout.

New Zealand Strike Indicators

New Zealand style strike indicators are comprised of coloured wool, which you attach to the leader with a short section of slim, clear elastic plastic tube using a special tool. The indicator’s distance from the fly can be adjusted relatively easily to fish shallow and deeper water, but the main advantage of this type of indicator is you can adjust the amount of wool and the color of the wool to make the indicator more or less bulky to avoid spooking fish. These yarn indicators are easy to cast and are the best choice for fishing for low and slow water as well as large, clever trout, or in areas that are heavily fished.

Foam indicators

Slit foam indicators are highly buoyant and highly visible and relatively easy to attach and remove to your leader thanks to a little rubber band holding the two foam halves together. They hit the water with slightly less impact than the bobber style when you are fly fishing, but are still more obtrusive than the New Zealand style strike indicators. The other disadvantage of fly fishing with this style of indicator is they can come dislodged more easily than other kinds.

Adhesive fold-on indicators

These are dead simple indicators – little bright-colored patches that fold onto the line. You can get sets in different sizes and colors giving you lots of options and replacements for when they fall off.

Indicator putty

Indicator putty allows you to form a small, brightly colored plug that you can attach to your line as an indicator. You can adjust the amount to the fly fishing situation making these a flexible option that are less intrusive than bulky indicators and heavier indicators. These indicators float, but not as high in the surface film as more buoyant styles of indicator.

A buoyant dry fly

The other option for for fly fishing with an indicator is to simply use a buoyant and bright dry fly such as a Stimulator, Humpy or Royal Wulff as the indicator with a dry-dropper rig. The big advantage of this method is the dry fly is less likely to spook trout and sometimes they’ll take it in preference to the nymph. The one weakness with this rig is it is more time consuming to alter the distance between the nymph and the indicator fly to cater for changes in water depth.

The easiest way to hit the desired depth is the remove or add line to the tippet by trimming it or adding new sections with a triple surgeon’s knot or double blood knot. The other thing to consider when fly fishing with a two-fly rig is that it is not as easy to cast and you need to throw slightly looser loops to prevent the two flies from becoming entangled.

How do you use a strike indicator?

To use a strike indicator, attach it to your leader at a distance from the fly line that will allow the nymph to drift close to the bottom in the kind of water you are fishing.

You will need to adjust the depth by sliding the indicator up and down the line to keep the nymph near the river bed as you move up the river and you are fly fishing at different depths from shallow riffles to deeper pools.

Can you fish the same way without an indicator?

Yes, nymph fishing can certainly be done without an indicator and many fly fishers prefer to fish this way. In clear water where you are sight fishing, you can remove the indicator and time the strike off the fish’s body language. When you see it shift left or right to eat the nymph you strike as it straightens and most times you’ll connect. The other thing to do when sight fishing is to strike when you see the flash of white from the fish’s jaw opening and shutting.

The other method is so-called tight line nymphing, also referred to as euro nymphing. With this method, the fly fisher doesn’t use any form of external indicator (although a bright color segment of mono is used to form part of the leader). Euro nymphing involves using a long rod and leader and careful line management by lifting and swinging the rod to create a natural drift close to the bottom for as long as possible. Takes are either felt or made when the angler sees the rainbow-colored mono jerks or stops.

What sort of flies can be fished beneath an indicator?


Bead headed nymphs are the most common fly to fish under an indicator: pheasant tail nymphs, hare and copper nymphs, Copper Johns and all other types.

These can be either tungsten or brass beaded nymphs depending how quickly you want them to sink and what depth you are fishing.

Remember that tungsten weighted nymphs will require a more buoyant or larger dry fly to keep them suspended.


A lot of anglers don’t know this, but you can also fish streamers under an indicator to if the water you are fishing has some decent flow. That’s enough to get the marabou or bucktail of the streamer moving nicely and induce a take if you are fishing upstream. An indicator is not necessary when fishing across and down (conventional streamer fishing) as you keep a tight line with this style and feel the takes.

Dry Flies

And sometimes an indicator is even useful fishing dry flies when you fish a tiny, drab colored dry right through the evening rise and it gets impossible to see – that’s when it is handy to have the movement of the indicator to use to see the strike.

Are strike indicators hard to cast?

Strike indicators do make your rig harder to cast, but the extent of this depends on the type of indicator and the conditions. For example, casting a foam strike indicator in high wind might provie a bit tricky, whereas a bobber or New Zealand style yarn indicators might be a bit easier to manage.

Overall, though, with a bit of practice you should be able to cast with all types of strike indicator relatively easily in most conditions.

Where should I attach the strike indicator?

Start with the depth of water and work backwards. You generally, especially when fly fishing freestone streams or rivers, to have your nymphs drifting close to the bed of the stream. Nymphs hatch from under rocks on the stream bed and trout are attuned to grabbing them as dislodge from the surrounds into the flowing water.

If you are fly fishing a shallow riffle, or other kind of skinny water such as the tailout of a pool, a foot or two from the fly is the right spot for the indicator, but when you are fly fishing deeper glides from waist deep to chest deep, you can slide the indicator further up the leader to get those flies closer to the bottom.

Should I retrieve or leave the flies static?

Dead drift is the way to fly fish when you are indicator nymphing. The nymph or nymphs should move at the same speed as the current as a general rule, so retrieving them accelerates the flies beyond the current speed and makes the presentation appear unnatural.

How should I fish flies beneath an indicator?

As I said, you need to dead drift the flies. You need to manage the line carefully to minimize slack without actually pulling the flies through the water. This means when you lift to strike it will be also instantaneous and avoid missed strikes.

How will I spot a bite?

Any time the indicator stops, goes under or gives a little shake (in the case of subtle bites), you should lift to strike. If you are managing your line correctly and staying up tight to the flies, even lifting from just above horizontal to say 50 degrees will be enough to set the hook. If it is not a fish, you can simply drop the rod back down and fish the remainder of the drift if you can.

Why do trout sometimes try to eat the indicator?

Some fish are in a surface feeding pattern and are looking upwards for their next meal. They might mistake the indicator for a beetle or another kind of terrestrial such as a hopper, so they make a swipe at the indicator. Sometimes they’ll boil under the fly, coming right up to it without actually eating it. Either the way, the result is the same – you have induced a rise without a hookup. It’s worth switching to a dry and seeing if you can pick up the fish that way when this happens. The one way to avoid the problem from the outset is to use a dry-dropper rig where the indicator is a bulky fly such as a humpy. That means you convert these strikes into hookups.

Why do strike indicators come in so many different colours?

Bright fluoro colors are very easy to see in both dull and bright conditions, so they are very popular for foam strike indicators, NZ style yarn indicators, adhesive fold on indicators, putty and the football indicator style.

However, these bright colors can be a warning sign to wily trout in hard fished streams. With yarn indicators you can blend the fluoro yarn with some white yarn to “dilute” the coloration or switch out the fluoro yarn entirely for white wool, to boost your chances against these clever fish.

Can I use a strike indicator in lakes as well as rivers?

Yes, for sure. Indicator fishing works really well in lakes with nymphs that are best fished static such as midges and stick caddis. Usually it is best on a lake to use a bouyant dry, such as a reasonably buggy mayfly pattern, as the indicator dry-dropper style, although you can certainly use any of the above types of indicator to good effect too.

Final Thoughts on Fly Fishing Strike Indicators

Fly fishing with strike indicators has its place and it can be the easiest way for novice fly fishers and those learning to fly fish to get on the scoreboard. Different fly fishermen and women have a different personal preference for which type of indicator they prefer – hopefully this article has given some guidance on which type of fly fishing situation each type of indicator is best suited to.

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Rick Wallace is a passionate angler and fly fisher whose work has appeared in fishing publications including FlyLife. He's appeared in fishing movies, founded a successful fishing site and spends every spare moment on the water. He's into kayak fishing, ultralight lure fishing and pretty much any other kind of fishing out there.
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