How to fly fish with a strike indicator

A strike indicator, bung or sight bob can make it easier to keep your flies at the right depth and spot takes. Check out our tips on using them.

How to fly fish with a strike indicator
© Fly and Lure
How to fly fish with a strike indicator
Picture copyright © Fly and Lure
How to fly fish with a strike indicator
Fly fishing tips Estimated reading time 13 - 21 minutes

What is a strike indicator?

A strike indicator or "bung" is a small floatation device which attaches to your leader when fly fishing and allow you to spot subtle bites or "takes" more easily.

Trout often mouth flies and spit them out several times before swallowing them or swimming off, so many very small bites go unnoticed. Not so with a strike indicator!

The other purpose of a strike indicator is to suspend your flies at a specific depth. Trout move up and down in the water column according to the time of day, temperature, movements of aquatic invertebrates and the intensity of the sun. If you can find the depth at which they're cruising you stand a much better chance of them spotting, and taking, your fly. The strike indicator lets you do that with precision.

Some purists don't like "fishing the bung" and liken it to float fishing, but it's widely used and very effective. It's particularly good for novices, children and those with poor eye sight, since the brightly coloured indicator gives you something easier to spot that merely watching the tip of your fly line.

Our kids all love fishing with indicators as it makes fishing more exciting for them. They've got something to watch and they get to see bites they'd never spot without an indicator.

How do you use a strike indicator?

There are many different styles of strike indicator (see below) but they all work in a similar manner. You simply attach them to your leader and your fly or flies will dangle vertically beneath at the depth you set.

If you think the fish are feeding high in the water you can place the indicator anywhere from a foot to a few feet from the point fly and they will be kept at this depth. If you think they're cruising deeper, then you can slide the strike indicator up to fish the flies in deeper water.

Picture copyright © Fly and Lure.

Can you fish the same way without an indicator?

Many people successfully fish flies such as buzzers without an indicator using a technique known as straight lining or straight line nymphing. This can be just as effective as fishing with an indicator, and it's easier to cast with an indicator attached, but it will be harder to keep your flies at the desired depth and it's harder (especially for novices) to spot takes. There's a lot more skill to straight line nymphing than there is to fishing the bung.

A few stillwater trout fisheries won't let you fish with a strike indicator as they consider it unsporting, but it's allowed at most places and it's a common technique in competition fly fishing. It's not for everyone though. At the stillwaters we fish, like Ellerdine Lakes, it's one of the most commonly used and most effective methods.

What sort of flies can be fished beneath an indicator?

In UK stillwater trout fishing, the strike indicator set up is most commonly associated with fishing buzzers. Ordinarily, fly fishers fishing buzzers would fish them as a team of three flies - one on the point (the tip of the line) and two dangling from droppers.

However, strike indicators can be used to suspend any fly, not just buzzers. They're useful when fishing small nymphs but are also deadly when fishing gaudy, modern flies like blobs and squirmy wormies.

They can provide a really novel way of presenting various flies in a way that many trout won't have seen before. It's worth trying the method the next time you're on the bank.

The orange blob can be deadly when fished beneath an indicator or bung.

Are strike indicators hard to cast?

Unfortunately some strike indicators can make casting more difficult, especially when it's windy. The bigger, heavier or bulkier the indicator, the harder it will be to cast.

On the other hand, the smaller, lighter and less bulky indicators often have less resilience and can sometimes be pulled under by the weight of the flies, so you may need to pack several types.

Heavier indicators will also mean you'll need to adjust your casting stroke by making it slower and with a more open loop. This can help stop droppers tangling and ensure your flies don't land on the surface in a tanged heap.

Where should I attach the strike indicator?

In most cases, the strike indicator will be attached to the leader immediately after the uppermost fly so everything else dangles beneath.

You can also place the indicator further down your leader and have flies positioned above it. Though this isn't a common approach, it can let you keep several flies much closer to the surface that you'd otherwise achieve without resorting to the so-called washing line technique, where a buoyant fly is used on the point to hang a pair of buzzers below the surface like trousers on a washing line.

Strike indicators keep your flies at the depth at which fish are cruising and make bite detection far easier.

Should I retrieve or leave the flies static?

Either technique works. On some days, fishing the flies completely static is the only technique that gets takes, especially on very cold winter days. However, the odd pull or a slow figure eight retrieve can also work wonders.

Another technique worth trying is to move the flies up in the water slowly and then let them drop. This is how buzzers move, so trout often take the flies as they're moving up or dropping down.

You can do this either with a long, slow pull of the line, or by slowly lifting the rod to 45 degrees and then lowering it.

How should I fish flies beneath an indicator?

It's dead easy. Simply attach your indicator at the desired depth so your flies will be suspended beneath, cast out gently using an open loop and a slowed down casting stroke and present them gently on the water surface.

After they've landed, do a long straight pull to remove any slack and keep the flies in line with your rod. Keep the rod tip down, just above the water surface, and fish them fairly static. Ensure you remove any slack using a figure of eight retrieve, otherwise you won't hook the fish if it takes the fly.

If it's windy (and indicator fishing often works best when there's a bit of ripple) you can let the wind make a bow in the line and move your flies round. As the line straightens out the bow, start twiddling the line back and often the trout will take the flies as they change direction.

Strike indicators are a great way for youngsters to improve their catch rate and see more bites.

How will I spot a bite?

Usually, you'll see the indicator twitch as the trout sucks up or mouths one of your flies, but more often than not the indicator will just go under or the line will suddenly tighten before you've even spotted that the indicator has gone.

To strike you simply raise the rod to 45 degrees and pull the line with your line hand and the hook will set. You'll probably get lots of tiny bites, but you'll also miss a lot of them as they're just fish mouthing the flies and spitting them back out. An indicator lets you see this activity, and an average angler wouldn't spot it without one.

Why do trout sometimes try to eat the indicator?

Trout are inquisitive fish and often sample things floating on the surface that look like they might be tasty, so it's fairly common to have the odd one try to eat your strike indicator.

This happens so frequently, especially during the warmer months, that some fly fishers tie or buy special strike indicator flies that have a hook built in. These so-called bung flies are worth considering if this keeps happening to you, as you'll really increase your chances of catching.

Why do strike indicators come in so many different colours?

Strike indicators are generally orange, yellow, pink or white because each of the colours can be seen better depending on the light conditions. It's worth having several colours in your pocket just in case you struggle to see the indicator due to the light or weather conditions.

Can I use a strike indicator when fishing rivers?

Yes, although some clubs might not allow their use. They're most commonly used in the US but their purpose in the river is more for strike indication than for suspending the flies at a specific depth as it is in stillwaters.

In running water the flies don't hang beneath the indicator as they do in stillwater, so you'd generally set the depth at one and a half times the water depth. This allows you to fish a nymph just above the bottom of the river bed, without snagging up too often.

The other benefit they have for river anglers, especially novice river fly fishers, is that they help you spot when the line is dragging. River trout don't like flies that are being dragged unnaturally and you can spot this much easier with an indicator attached.

Their use on UK rivers isn't that common though, and lots of river anglers frown upon their use.

What type of strike indicator should I choose?

There are loads of different types of strike indicator on the market. They all have their pros and cons, so you might want to try a few and see what works best for you. Here are a few of the most common strike indicators for fishing the bung method:

Fish Pimp Strike Indicator

The Fish Pimp Strike Indicator is one of the most common of the rugby ball style polystyrene strike indicators. These have a slit down one side into which you place your leader which is then locked in place using a rubber tube.

There are several ways to attach the to your line. Most people just put the leader behind the rubber but sometimes they fall off. You can minimise this by wrapping the rubber tube around the leader before you insert it, but this is rather fiddly, especially when your hands are frozen.

Fish Pimps and other rugby ball shaped indicators are very popular.

These rugby ball strike indicators are quite light, aerodynamic and easy to cast and fairly buoyant. They can be tricky to attach, sometimes fall off or snap in half, and the rubber sleeve inside often goes hard which makes them impossible to use. They're far from perfect. 

For what they are, they're also quite pricey at about £5 for 5-6 of them. The rugby ball shaped indicators are probably the most versatile ones around and the ones I use most, but my personal preference now is to avoid the Fish Pimp ones. I've bought several packets in which the rubber is so stiff I've not been able to use them, so now look for those brands that come with silicone rubber sleeves instead.

Orvis Thingamabobber

The Orvis Thingamabobber is pretty much indestructible and extremely buoyant, so at £6.50 the five you get in a packet will last you far longer than the five or six brittle polystyrene rugby ball style strike indicators.

The Thingamabobber can be attached easily by pushing a loop of line through the hole in the base of the indicator and pulling it over the back of the indicator. It can be adjusted or removed by loosening or removing the loop.

The Orvis Thingamabobber is a very buoyant strike indicator.

While these are extremely visible and buoyant in very poor weather conditions, the downside is that the slightly heavier weight can impede casting a little (especially on lighter rods) and they can leave a little kink in your leader. This can pull out if you stretch the line or run it through a line straightening pad, though. 

As Thingamabobber's stick out sideways, they're not quite so streamlined, so tangles can occur more often than they do with the more aerodynamic rugby ball shaped indicators.

Airflo Airlock Strike Indicator

Airflo's new Airlock Strike Indicator is most similar to the Orvis Thingamabobber in that it's a small lightweight sealed ball. What differs is how it attaches to the line.

Airflo Airlock Strike Indicator - easy to use, horrible to cast.

The Airlock Strike Indicator has a little slit of rubber in the base into which the leader slots, over which a small plastic screw nut is tightened to keep the indicator in place. This makes attachment easier than with the Thingamabobber and has the benefit of not leaving any kinks in the line.

The downside is that these are much more expensive at £7 for three (though they should last ages unless you lose the screw nuts) and that they are, in my opinion, the worst of all indicators to cast.

Stick-on strike indicators

As the name suggests, stick-on strike indicators stick onto the line. They're made from very lightweight, but extremely buoyant foam which has adhesive on one side. To attach one you simply peel off the indicator or the protective layer from the sticky side and wrap them around your line in the desired position.

Stick on indicators are easy to attach, but fiddly to remove or reposition.

They're very quick and easy to use and are fairly easy to see and cast, even on very small light rods. The downside is that they're single use, and they're not easy to adjust or remove, so you'll get through lots of them in a single session.

Look for those which have a solid colour as these are more visible than the ones with just a coloured surface. 

Our children tend to favour these stick on strike indicators as they find them much easier to attach that all of the other kinds, as well as easier to cast without tangles. Getting them off afterwards isn't quite so easy, though. You'll either need to tear them off or snip the line.

New Zealand Strike Indicator

The New Zealand Strike Indicator is rather different to the other indicators mentioned here. The indicator itself consists only of a very small piece of brightly coloured sheep wool (dyed, not from a rare breed of brightly coloured sheep).

Sheep wool is rich in oils and naturally fairly buoyant, so it can support surprisingly heavy flies. It's also very light, so these indicators are easy to cast even on very small, lightweight rods. My tiny Orvis Superfine Touch can handle casting one of these without a problem.

New Zealand Strike Indicator in place.

The wool is attached to the line using a New Zealand Strike Indicator Tool. This handy little gadget, clearly made from a sewing needle, lets you slide up a tiny silicon rubber sleeve onto a loop of your leader. You place a little chunk of wool in the loop, then pull up the sleeve and pull the line from either side.

These are pretty good and everything is completely reusable, so the £13 or so for the New Zealand Strike Indicator Tool set isn't really that bad value, as it should last you for years.

The downside is that the wool can get waterlogged so can require regular replacement or applications of floatants such as Gherke's Gink to keep it on top of the water. They're probably the best indicator for presentation too and are unlikely to spook even wary trout.

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