One nymph or two, and how far apart

Two nymphs cover more water and get down sooner; one nymph casts more accurately, tangles less, and lands big fish more safely. The published rigs fish two where the rules allow it, about 50 cm (20 in) apart, the heavier fly on the point and the lighter one on a short tag above it. Before anything else, check the rule of the water you fish: many waters allow only one fly. When to choose a dry fly, one nymph or two, or a dry-dropper is one of the things I teach in competition training, and this article is the reasoning behind the choice.

My background is more than ten years of competitive fly fishing, where the number of flies and the distance between them is set by the rules and checked by a controller. That is why the figures below are exact where the rule is exact, and honest about where good anglers disagree.

The short answer

The sources behind each line are in the sections that follow.

What a second nymph does that one cannot

The strongest case for two flies is a particular presentation. The point fly, the heavy one, rides in the slow water near the bed. The upper fly, on its tag, is pulled along at the point fly’s speed while staying above the slow layer, where a single fly on a tight line never sits for long. The pair also gets down sooner, because the combined weight is doing the sinking, so each fly can be smaller than a single fly would need to be (Swentosky, Troutbitten, 2024).

More flies cover more of the water column (Durrant, MidCurrent, 2024). And a light fly behind a heavy one brings takes from large trout that the big fly alone would miss, in Swentosky’s reply to a reader (Troutbitten podcast, 2024).

What it costs

Tangles

Two flies tangle more, and cast less cleanly. A rig that lands in a knot has fished nothing. With one fly the angler casts with more accuracy and more intent, and that is a real difference in a pocket under a branch (Troutbitten podcast, 2024, episode description and comments).

The drift

A second fly gives the current a second thing to catch. In broken, complex water the two flies drift in two lanes and fight each other, which is why some anglers shorten the spacing there, or go to one fly (Swentosky, 2024).

Big fish and the loose hook

A reader’s case against two, in detail: a fish hooked on the point fly can be caught by the loose dropper on its tail; the free fly snags the bed or a branch during the fight; and small fish take it mid-fight (Troutbitten podcast, 2024, reader comment). Dave Southall fishes one fly for grayling partly because two of his waters require it, and partly because trailing flies have brought him double hook-ups and snags (Southall, Sunray).

A dispute about sinking

One reader of the Troutbitten podcast argues that two separate 3 mm nymphs sink at the rate of one 3 mm nymph, not of a 6 mm one; Swentosky’s article says the combined weight gets the pair deeper sooner (Troutbitten podcast, 2024, reader comment; Swentosky, 2024). This article leaves that open. What is not in dispute is that more flies cover more of the water column, and that one fly casts better.

How far apart: 30 to 50 cm, and the 50 cm rule

Spacing as published:

• About 20 in (51 cm) between a heavy point fly and a small tag fly, in Sean Crocker’s rig as Josh Miller describes it (Miller, Fly Fisherman, 2025).
• 20 in (51 cm) in Troutbitten’s standard formula, shortened to about 12 in (30 cm) in complex currents to keep both flies in one lane (Swentosky, 2021; Swentosky, 2024).
• 18 in (46 cm) in George Costa’s recipe (Costa, 2016).

In competition the figure is fixed. Under the FIPS-Mouche rules, 2025 edition, flies “must not be closer to each other than fifty cm”, measured eye to eye with the leader hanging freely, and at most three may be fished, the number set for each event in its rule modifications (article 29.5). So 30 cm would not pass a controller.

The sources add up to this: 50 cm is the default, it passes a competition check, and it keeps the flies far enough apart to fish two depths. Shorter spacing is a choice for one kind of water, not a starting point.

Point and dropper: which fly where

The heaviest fly goes on the point, at the end of the tippet, and the lighter fly above it on the tag (Costa, 2016; Miller, 2025; euroflyangler). The heavy fly anchors the rig in the slow layer and pulls the tippet straight; the light fly rides above it.

In competition a dropper must be of the same or a smaller diameter than the leader it leaves, it must carry a fly, and neither fly nor dropper may slide along the leader (articles 28.5 and 29.6). An empty dropper is not allowed.

How heavy each fly should be, in grams, is in how heavy should a euro nymph be.

The tag: length and knot

Tie the tippet to the leader, or to a fresh piece of tippet, with a surgeon’s knot and leave one tag end 8 to 10 in (20 to 25 cm) long; the dropper fly goes on that tag. When the tag gets short from changing flies, cut it off and clinch a new piece of tippet above the knot (Orvis dropper lesson). Devin Olsen ties a triple surgeon’s knot and uses the long waste end as the tag; at the tippet ring, a 6 in (15 cm) tag takes a dry fly (Olsen, in a reply under his Gink & Gasoline piece).

How many flies are allowed

Three answers, and the first one is yours to find out:

1. The water you fish. Many rivers allow one fly only, some allow two, and the number can change with the stretch and the permit. Check the rule before you tie on a second fly. The rules of the Montenegrin fly zones are not written here: ask me when you request your dates, and every permit is inside my price.
2. In competition. Up to three flies, not closer than 50 cm eye to eye; each event sets the number it allows (FIPS-Mouche rules, 2025 edition, article 29.5). The whole rule set is in FIPS-Mouche rules explained.
3. For learning the dry-dropper. One nymph under the dry fly before you try two (Olsen, Gink & Gasoline).

The third choice: a dry fly on the dropper

When fish are rising, the third choice is a dry fly on the dropper with a nymph below it. The simplest version keeps the euro leader: replace the dropper nymph with a dry fly buoyant enough to hold the nymph up, grease the sighter and the section above the ring, start with a nymph of 2.8 mm bead or more so the leader turns over, and cast with short wrist strokes on an oval path (Olsen, Gink & Gasoline). Or, for rising fish, put a dry fly on the dropper, or change to a classic tapered leader (euroflyangler).

Why the dry fly and not just the sighter? A sighter alone cannot hold up anything heavier than about a #16 tungsten nymph; a dry fly can (Swentosky, 2017). The dry fly is the indicator and a second chance at a fish.

Why grayling refuse a dry fly at all is in why grayling refuse dry flies.

When one is better

As the sources put it: when conditions call for it, Swentosky often clips the tag fly (Swentosky, 2024); under low branches and at odd angles, accuracy suffers as the rig gets heavy, and one reader puts the limit near 0.6 g (Troutbitten podcast, 2024, reader comment); and where the rule says one, one (Southall, Sunray).

One fly is not only the beginner’s rig. In the sources above it is also the rig for the hardest casts of the day.

How I teach the choice

The choice between a dry fly, one nymph or two, or a dry-dropper is a named part of my competition training, with the leaders, the rods, the approach, what to cover first and how to read water. I teach euro nymphing on a guided day too, if you want it. The rivers I guide are grayling rivers with brown trout beside them; the wild euro-nymphing river among them is the Ćehotina, and the Ljuča is the hard dry-fly water with the biggest grayling. What each river asks of the nymph is in euro nymphing in Montenegro, and the whole country is in fly fishing in Montenegro: the complete guide.

For the leader behind the flies, see leader, sighter and tippet length and micro leaders for euro nymphing.

Questions

How far apart should two nymphs be?

About 50 cm (20 in). That is also the minimum in competition, measured eye to eye. Some anglers shorten to 30 cm (12 in) in tight, complex currents (FIPS-Mouche rules, article 29.5; Swentosky, 2024).

Which nymph goes on the point?

The heaviest. The lighter fly goes on the tag above it (Costa, 2016; Miller, 2025).

How long should the dropper tag be?

20 to 25 cm (8 to 10 in) when tied; replace it when fly changes have shortened it (Orvis dropper lesson).

How many flies can you fish in a competition?

Up to three, as the event allows, and never closer than 50 cm (FIPS-Mouche rules, article 29.5). On an ordinary river, the rule of the water decides.

Is one nymph ever better than two?

Yes: for accuracy in tight places, for fewer tangles, and when landing a big fish matters more than a second chance at a take (Troutbitten podcast, 2024).

When should I fish a dry-dropper instead?

When fish are rising, or when the nymph has to be held up and a sighter cannot do it (Swentosky, 2017; Olsen, Gink & Gasoline).

Reading this tells you the options. Choosing between them in front of a run, with the rule of the water and the fish in view, is learned on the river, and I teach it in competition training or on a guided day, with my own nymphs and dries for these rivers if you want them: see flies. Tell me your dates and what you want to work on. Request your dates.