Comprehensive fly fishing indicator guide

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Simply put, a fly-fishing strike indicator plays three roles. A visible object, which floats and does not spook wary fish. The indicators movement through the water can be used to detect strikes.

Factors to consider when choosing an indicator

  1. Fly weight (Heavy flies need larger indicators)
  2. Water condition (The more turbulent the water, the more buoyant the indicator)
  3. Fish Wariness (Spooky fish, need smaller more natural indicator)
  4. Castability (Larger indicators are harder to cast)
  5. Adjustability (Indicators position needs to be adjusted to fish varying water depths)


In our Indicator buyers guide we rate many popular indicator products by the five key factors above. You can read it here (coming soon).

Types of fly fishing indicators

Fly fishing indicators must be visible
White indicators contrast nicely against dark surfaces

Fly fishing indicators come in many sizes, materials and designs. Indicators are made from both natural and synthetic materials. All fly fishing indicators need to float on the water surface and be highly visible. Ideally, they will also be lightweight, small and streamline not to interfere with the cast or to cause additional drag.

Wool and Yarn: Wool is a traditional and time proven natural indicator. Greasy lanolin rich wool taken from the farmer’s fence often floats the best. A great option for anglers in the United Kingdom, Australia, and New Zealand.

Wool is naturally buoyant, thanks to its large surface area to weight ratio and naturally occurring lanolin oils. Eventually it does become waterlogged, so applying oils and other floatants can help keep it afloat. Larger amounts of wool can be used to keep larger flies afloat.

White wool contrasts nicely against the dark water surface. Dyed wool in bright colors is even easier to see. Don’t use spun wool for an indicator natural fibers work best.


Various synthetic yarns share many of the same characteristics as wool. Some contain very lightweight and fluffy fibers. Synthetic yarn has grown in popularity because of its superior buoyancy and brighter colors.


Foam: Foam indicators have excellent buoyancy. They are typically a small, brightly colored balls of foam which are attached onto the fly line. Foam is best used in turbulent water with a lot of downward pressure.


Stick on: There are also little Stick-on Oval indicators. Being foam, they offer good buoyancy. They are among the quickest indicators to apply, just remove the back tape and pinch over the line. They are non-damaging to the line. although not as durable as some indicators. The adhesives will eventually fail.

One downside, they are difficult to remove or reposition along the line.

Hard plastic balls. Rigid plastic balls are a common indicator design. The line threads through a tiny hole, then secured with a plastic pin or toothpick. These indicators offer good visibility and excellent floatation.

Downsides include that you must remove the fly before threading through the leader. They are also relativity bulky, causing some disturbance to the presentation. These balls are best used in big water, strong current fishing where visibility and floatation is more important than stealth and precision.

Bio-putty: Is very easy and quick to apply. Simply form a small ball with it, and squeeze around the leader. The putty hardens on contact with cold water. Applying the putty to the knots helps prevent it flying off during casts.

Using a dry fly as an Indicator

We have all seen it. Our fly is gently drifting, and up comes a hungry trout eager to feed. The trout turns, opens its mouth wide and engulfs the indicator. Moments later, the trout spits it out before returning to the depths.

This is the primary reason many anglers indicator of choice is a dry fly. In calm conditions, a buoyant and visible dry fly kills two birds with one stone. Its bright wings plays the role of an indicator, while at the same time it is a dry fly.

Best dry flies to use as an indicator.

Almost any dry fly can be used as an indicator. It only needs to be buoyant enough to stay afloat.

One of the most popular dry flies to use as an indicator is the Royal Wluff. The royal fluff does a good job at imitating mayflies and tiny terrestrial insects. Bright white hairs on the back make it very visible from afar. The Klinkhammer is a popular alternative.

Simulator, the simulator is a large fly with a lot of buoyancy. It represents large terrestrial insects. It works well during the hot summer months when there is plenty of insect activity. A cicada imitation is a good option during the Cicada hatch in New Zealand.

Foam Bugs. Small foam bug flies float well while resembling insects. One such example is the Unsinkabeetle. In small sizes they represent house flies, while the larger sizes represent bigger terrestrials.

Indicator setup

Several factors determine the ideal location of an indicator. The most common factor is the depth you wish to fish the nymph. Placing an indicator towards the fly line allows the nymph to sink deeper into the water column, in contrast moving an indicator towards a nymph means it would drift just below the surface.

How to attach an indicator

The most common method to attach a yarn or wool indicator to the leader is with an open indicator knot. This knot is very easy to tie but is quite weak. Avoiding tying it in the tippet or thin portions of the leader.

Aniother variation is to tie a half hitch and thread the indicator through the loop then tighten. Then create a second loop over the half hitch securing it in place and preventing it from moving. Trim the yarn to the desired size and start fishing.

To remove the indicator, pull the indicator fibres apart which would open up the knot. All knots weaken the breaking strain of the line, so avoid tying them in lightweight tippet material.

New Zealand Indicator tool

The purpose of the New Zealand indicator tool is to install yarn or wool indicators.

The indicator tool is a finesse tool somewhat resembling a Latch Hook. The tool is easy to use. Start by creating a tiny loop in the line. Before inserting a tiny piece of tubing over the loop. Then thread the indicator fibers through the loop. Close the loop by squeezing the tiny tube against the yarn.

It is a knotless method for installing indicator yarn onto the fly line. The yarn is easy to remove by pulling the tubing away. It is also easy to move the indicator along the line. Quite a versatile little system. The tool makes it easy to use a precise amount of yarn. Allowing for bigger or smaller indicators.

Adjustable fly fishing indicator

Most fly-fishing indicators are adjustable, meaning they are easy to remove or relocate along the line.

The most adjustable indicators once installed are the hard plastic balls. It is possible to change their location by removing the locking pin and sliding the ball to its new location.

Yarn or wool indicators installed using the Indicator tool method are also very adjustable. Just loosen the locking tube, and slowing work the yarn along the line.

Bio-putty indicators need to be removed, then rolled into a new ball and reapplying. Bio-putty does slip so most users apply it around a knot in the line.

The less adjustable indicators are the stick-on pads and dry flies. Stick-on pads must be removed before replacing with a new one. Dry flies need to retied to its new location.

Fly-fishing without an indicator.

It is possible to fly fish with nymphs and tiny wet flies without an indicator. There are several reasons to do so. The first is simplicity can be beautiful. Fishing with just a fly allows for more casting precision and graceful presentations.

In very clear water when casting to feeding fish. It is possible to see the trout take the nymph. When a trout opens its mouth to feed, you can briefly see the whites of its jaws flash. This is the indication to strike.

When sight fishing, precision of presentation is of most importance. Fishing with an indicator not only makes precision casting harder, it might actually spook the fish.

Do not use indicators when fishing deep water

When fishing deep water, you do not want an indicator. One of the primary purposes of an indicator is to keep the fly or nymph close to the surface. When trying to fish deep water the indicator simply pulls the fly back to the surface. If you add even more weight, the indicator gets pulled under and creates unwanted drag.

Similarly, when actively fishing streamers indicators simply get in the way. The conventional streamer fishing method is to let it naturally swing across the current. Before giving it a few strips. With the line under tension, you should be able to feel any strike.

How to tell when a fish strikes?

Detecting strikes without an indicator can be difficult. It is a more advance technique. Luckily, there are subtle ways to tell when a trout has taken your fly.

The most common solution is to closely watch the tip of the fly line. Just like an indicator It would ‘unnaturally’ jerk and move when a fish makes contact. It takes concentration and keen eyesight, but is a proven way to detect takes.

If you are sight fishing, and can see the trout. Then watch for movement. It is normally possible to see a trout turn its head and open its mouth when taking a fly. This is the indication to strike.

Finally, is to fish by feel. With minimal slack in the line, you can feel the wiggle and weight of a hooked trout. Fishing by feel requires the line to be under tension. This method is often used when actively fishing with streamers.

My Recommendations on the best Indicators for Fly fishing

Factors to consider when choosing an indicator

  1. Fly weight (Heavy flies need larger indicators)
  2. Water condition (The more turbulent the water, the more buoyant the indicator)
  3. Fish Wariness (Spooky fish, need smaller more natural indicator)
  4. castability (Larger indicators are harder to cast)
  5. Adjustability (Indicators position needs to be adjusted to fish varying water depths)

AIR-LOCK Strike Indicators

Air-Lock makes their strike indicators out of a low-density foam. They are quick and easy to use and are a breeze to adjust. Simply unscrew the little end nut and lay the leader into the grove. Then lock everything in place by screwing the nut down tight. They come in three sizes (1/2”, 3/4”, and 1” sizes), and three colors (white, pink and orange).

The lightweight foam construction allows for easier casting but they certainly more noticeable than a pinch of yarn. The nature color locking nut assists to camouflage the indicator when floating but it is still going to spook wary trout.

Apparently they are now entirely biodegradable so losing one will not litter the environment with more long lasting plastic.

Overall, they are a very buoyant, easy to lose strike indicator perfect for bigger water applications and casting to less wary fish.

Buoyancy5/5
Visibility5/5
Stealth1.5/5
Castabiltiy2/5
Ease of use5/5
Durability4/5

Thingamabobber

Thingamabobbers are hard plastic strike indicators. They are highly visible and very bouyant. Perfect for fishing heavy nymphs through fast flowing water. The weight does impact on casting, but the centrally located hole helps compensates for the additional bulk. These are not a strike indicator for precision casts.

In my local rivers, the wary trout swim a mile the moment such an indicator lands. But, in big water with less wary fish they excel.

To rig first thread the leader through the hole in the thingamabobber, and accurately position it. Then secure in place by sliding the plastic pin into the hole. Once secure it is very unlikely to move. To move the thingamabobber simply remove the pin and reposition. It could not be easier.

The thingamabober comes in five colors and four sizes (1/2″, 3/4″, 1” and 1¼”.)

Buoyancy5/5
Visibility5/5
Stealth1/5
Castabiltiy
2/5
Ease of use4/5
Durability5/5

Loon Biokstrike

There are several putty indicators on the market, and Loon Biostrike is one of the most well known, It is a reusable, biodegradable and environmentally friendly.

With wet fingers, roll the putty into a tight ball then pinch it anywhere on the leader. Applying it around knots makes it less likely to come off while casting. If you want to move, or remove the putty simply wet your finger and peel it off. It can be stored back in the container and used again.

Putty comes in a range of high visibility colors. I have not seen it in recent years, but their use to be a glow in the dark version for night fishing. The putty floats reasonably well, and can be a good indicator when fishing small dry flies. For greater floatation, simply increase the amount of putty.

Buoyancy2.5/5
Visibility4/5
Stealth4/5
Castabiltiy
4/5
Ease of use5/5
Durability2/5

Palsa Pinch on Strike Indicators

These were the first indicators I ever fished, and I still keep a few in my vest. These indicators can not be more simple. Just peel them off the backing and stick them around the leader. These strike indicators are made from foam with an adhesive backing. When lake fishing, one indicator is enough to float almost any fly. When fishing faster turbulent water multiple indicators can be applied to increase buoyancy.

They are a one time use only indicator, they can not be repositioned. The adhesive is strong, and they are unlikely to fly off during casting. They can be a bit tricky to remove and sometimes leaves a sticky residue on the line.

Buoyancy3/5
Visibility4/5
Stealth3/5
Castabiltiy
4/5
Ease of use5/5
Durability4/5

Wool / Yarn

Plain wool makes an excellent indicator. It floats, casts and lands gently. A small wool indicator is no more difficult to cast than a dry fly.

Growing up on a sheep farm, I have a ready supply of natural wool which I tie to my leader using an Strike Indicator Loop knot. It is a bit more time consuming to tie and to move, but it results in very streamline casts at no expense.

Many companies sell natural wool, and synthetic yarn which also work well. Crafting stores often sell raw wool in bulk for the same price as a little sachet sold to fly fishermen. Applying a floatant can help keep clean wool afloat.

A wool indicator can not be beat for delicate presentations to wary fish. I even had trout, ignore my dry fly and take the indicator.

Buoyancy3/5
Visibility4/5
Stealth5/5
Castabiltiy
5/5
Ease of use1/5
Durability3/5

New Zealand Strike Indicator System

The New Zealand Strike Indicator is a system to apply wool indicators. It makes the wool quicker and easier to attach to your leader. It is also very simple to move along. It maintains all of the same benefits as wool but at a much higher price.

Buoyancy4/5
Visibility4/5
Stealth5/5
Castabiltiy
5/5
Ease of use4/5
Durability3/5

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