More or less everyone will have noticed the huge variety of strike indicators and bite detectors available on the market, in addition to those that many anglers make themselves for the same purpose. This is no coincidence and, of course, it responds to a real demand and a real need—one that anyone who has experimented with different nymphing techniques will have become aware of.

Before getting started, I’d like to point out that, as a non-competitive angler, I don’t feel constrained by any additional regulations, and that I choose and develop my signalling techniques solely according to fishing conditions, the type of water, light conditions, the nymphs I’m using, the weather, and a number of other variables—including ethical ones—which I’ll try to describe as clearly as possible below.

Indicators that fish: flies

Whenever conditions allow, I’m a strong advocate of using dry flies to tell us what’s happening with the dropper or tag fly—in other words, the fly that is fishing subsurface, which, as we explained in another article, doesn’t necessarily have to be a nymph or be weighted. The reason is very simple: if we choose flies that combine visibility and effectiveness, we’ll be fishing with two flies and can get takes on either of them, thereby increasing our effectiveness.

Knowing how to choose the right size and colour of dry fly depending on the weight of our nymph, water colour, current speed, and light has its subtleties, but as a general rule, deer hair patterns, duck patterns, foam flies, or parachutes with posts in different colours usually do the job. As a recommendation—especially if you fish this way often—I’d suggest tying the same fly with posts or high-floating elements in different colours. It’s incredible how much our ability to detect a fly can change under different light conditions.

Another headache we often face is dropper length. How far below the dry should the nymph drift? This is so flexible a topic that I’d barely dare to write about it, but as a guideline, we could say that it’s not just about the depth we want the fly to fish at. The shorter the dropper, the more “anchored” the nymph will be to the dry, creating drag on multiple axes and resulting in a less natural presentation in the eyes of the fish. Personally, I like to go as long as possible to achieve the freest drift I can—without, of course, snagging every other cast and without the dry fly losing its second function, which is strike detection.

Tippet as indicator

Primarily, these are tippets of different colours and shapes which, used together or separately (we can combine different tippets to create contrast depending on light, water colour, and bottom), help us follow the drift of our nymph or nymphs and detect small changes in speed or pauses that we must learn to interpret as takes. Naturally, if we’re fishing tight-line, Polish-style, or with the rod tip high and tension throughout the system, we should aim to maintain that tension to feel the takes—but these threads are still helpful for judging depth, drift speed, and whether the flies are fishing where we want them to.

Coiled indicators (springs)

Also made from fluorescent threads, this indicator was developed in competition fishing to get around competitive regulations. Its low weight and shape allow it to “float” in the surface tension of slower water, helping detect takes when fishing light nymphs with a classic, natural drift. In my view, and outside the competitive environment, it adds absolutely nothing for anglers looking for something that both supports their nymphs and serves as an indicator in slow water.

We can also use paints, markers, waxes, and other products to colour our regular leader material. This gives us the same type of indication as fluorescent threads, with the advantage—especially with waxes—that we can easily apply or remove them. In general, they also eliminate extra knots, which are often weak points in the leader and a nuisance when it comes to tangles.

FLOATING INDICATORS

These can be found in most tackle shops. Most of them, however, are not designed with the kind of fishing we encounter in Spanish waters in mind, and are therefore of limited usefulness. I’m referring to oversized fibre pompoms and fluorescent corks in various shapes, for example.

We can, however, modify or replicate these indicators to suit our own waters. For years, I used tying fibres like “parapost” to signal while nymphing. Using just a few fibres, I tied a simple knot around my tippet at the desired distance from the fly, trimmed it down, leaving a small ball with a couple of tiny wings. Believe it or not, once greased it floated quite well, and given the wide range of colours available, it became a tool suitable for almost any lighting condition.

For a few seasons, with the help of a fishing buddy, I also drilled brightly coloured foam cylinders 1–2 mm in diameter, with variable lengths (1–3 cm). We inserted a pin and left them ready to slide onto the tippet when needed on the water. Lightweight, discreet, they cut through the air well during the cast and are highly visible. The downside? They take work. That said, I believe some brands now sell something very similar.

Among all of these, and given its flexibility of use, Biostrike is, in my opinion, the most adaptable to any type of water—and it’s what I use today in most situations. Why?

Because it allows me to do almost anything with it—and I mean almost anything:

  • It can be a nearly unsinkable 3 cm “cork” capable of holding up a tungsten-bodied fly (though I don’t recommend this due to casting weight and lack of subtlety).

  • It can be a tiny pellet—or several—ridiculously small and discreet, capable of supporting some weight, highly visible in most conditions, and allowing us to instantly change its distance to the nymph(s) or remove it in a split second, switching to dry-fly fishing if the leader allows.

  • It can be a wax. A wax? Yes, a wax.

Years ago, by accident, when hastily removing a series of small Biostrike pellets, I noticed that the marks left on the nylon were perfectly visible and caused that section to float. Over time, I refined the application method and now do it deliberately: I take a generous pinch of Biostrike between my fingers. It helps if it’s warm—or as warm as possible—since its viscosity increases significantly when cold. With this mass between my fingers, I pinch the leader and move up and down along it in the section I want to mark. You’ll see a thin film of Biostrike being deposited on the leader. Once the desired length is coated, you can wet it and you’re ready to fish.

This gives us a versatile indicator that allows us to fish discreetly in slow water with a natural drift and some buoyancy, or to fish tight-line, aerial, or contact styles. To remove it, simply rub again with your fingertips; the heat from friction will leave the leader clean once more. (See the last photo in the article to see how it looks.)

Considerations when choosing one system or another

Each of these signalling techniques has its pros and cons, and depending on how we fish and the waters we frequent, some will be more useful than others. Still, there are a few general considerations worth mentioning.

First, colour and contrast with the environment—water, bottom, surroundings. This is 100% subjective. Not everyone perceives colour the same way or sees certain tones equally well. My advice is to carry several colours, just as with flies, and sometimes combine them in sections to create contrast. Personal recommendation: a couple of fluorescent colours, white, and occasionally black.

Second, the technique being used. Especially over the last 10 years or so, since the explosion of tight-line nymphing, talking about “nymph fishing” has become confusing, as a large portion of anglers equate it exclusively with tight-line methods and their variants. But this world goes far beyond that. You can fish nymphs by casting—yes, casting—with your fly line: upstream, downstream, dead-drift, sight-fishing or blind, in any type of water—riffles, flats, and pools. Naturally, a Biostrike pellet has no virtue for tight-line fishing, where coloured threads, waxes, or paints are the better option. But that same pellet or greased fibre can be extremely useful when fishing a dead drift with longer casts.

Next is casting influence. Many of these systems add weight and bulk, which inevitably creates casting issues. This becomes especially problematic in windy conditions, where good casting technique really shows its value, and where the added drag of a tandem dry-nymph rig, an indicator pellet, or a pompom significantly hinders us. As a general rule, when casting weighted flies—especially in multi-fly rigs with a clear hinge effect and their own inertia—it’s advisable to use an oval cast, which protects both us and our gear from being struck by something moving fast and armed with a hook.

Then there’s drag. When nymphing, we add an extra axis of drag. Even though fish are often less selective than when feeding on the surface, presentation remains our top priority: the fly must drift as naturally as a real insect. Adding an indicator can help or hurt, depending on circumstances. A floating indicator or dry fly anchors the nymph to the surface, where water speed is usually faster than below. In many situations, the indicator will pull the nymph, speeding up the drift—bad news. Add wind into the mix, especially blowing upstream, and it can slow the indicator enough to create drag by braking the nymph’s drift. In such cases, it’s better to use systems that don’t influence the drift—or do so minimally—such as coloured threads, paints, or the Biostrike wax technique described earlier.

Finally, the fish—the damned and beloved fish. Trout and their preferences matter greatly. I’ve dealt with fish that wouldn’t tolerate any indicator above them, and others over which you could sail an ocean liner. I’ve seen, in New Zealand, heavily pressured fish spook at a dry-dropper tandem, yet have no issue with the same nymph fished alone with a Biostrike-waxed leader section. In short, we should use our knowledge and powers of observation to choose the solution that gives us the best chance of success. Obviously, a trout feeding on tiny nymphs in a shallow margin isn’t the place for a cork acorn or a feather duster—but it’s also obvious that no matter how good we are at sight-fishing, there are situations where we simply won’t detect every take in time. And we’re no less of a man or angler for using a tool to help us.

To wrap up, and echoing a reflection I made in my previous article about tippets: purists come in all shapes and colours, and this topic is no exception. We’ve all heard someone puff their chest out with “I don’t use indicators, I don’t need them,” or the dismissive comment, “That’s basically fishing with a cork.”

Honestly, I’ve been sight-fishing for 25 years. It’s been an obsession throughout my evolution as an angler—from fishing with live grasshoppers or larvae and a pole, to today. I’ve fished all kinds of rivers and waters across Spain and around the world, always seeking that challenge. Along the way, I’ve faced fish with wildly different behaviours and temperaments. And yes, I’ve missed many fish out of sheer arrogance—believing I could see or intuit everything, in any water, depth, light, and distance. I still miss them. Because every now and then, a dose of humility reminds and teaches me. And I still get angry—at myself, not at the fish or the light. We’re grown-ups; excuses are beneath us.

The point is this: in competitive environments, many of these signalling techniques are forbidden, which has pushed competitors to develop alternative methods—and to evolve as anglers, learning to detect nearly imperceptible takes. But outside that competitive framework, there’s room for improvement and for using these tools according to our needs.

As for me, I’ll keep getting mad at myself like a monkey every so often—because spotting a trout, sensing a movement, a colour change, a flick of an operculum or fin, setting the hook and watching it twist… that gets me going. A lot. It’s one of the things I love most about this world. But I’ve also learned that sometimes I’m far more likely to miss than to hit—and that using the right help at the right time dramatically increases my chances of success. Many of the fish I catch, I owe to that help. Sometimes I wouldn’t have needed it—but other times… And I don’t consider myself a worse angler for it. Quite the opposite.

P.S. Where do I look when I’m sight-fishing and decide to use an indicator because I’m not sure? The fish? The indicator? Sorry—both at the same time. It’s not easy, but it can be done. Why? Because if you can detect a take with your eyes, never—never, never, never—wait for the indicator to tell you. If you do, sometimes it’ll be too late. Because no matter how many tools we have, fishing is fishing, and there will always be unfinished business and fish that make us come back again and again.