Nymph flies for trout and grayling

Choosing a nymph by fishing depth

The most detailed imitation is ineffective if it passes above or below feeding fish. Current speed, water depth, leader diameter, fly weight, line type and cast angle all affect the path of a nymph. Select enough weight to enter the feeding zone while retaining control; additional weight is not automatically an improvement.

Main nymph constructions

• Unweighted nymphs offer a gentle entry and a natural drift in shallows, slow water and the upper layers. Their depth can also be controlled by the leader or another fly where rules permit.
• Weighted nymphs carry weight in the body or another part of the dressing and may preserve a beadless, natural head profile.
• Bead-head nymphs combine weight with a distinct head or trigger point. Sink rate depends on bead material and size as well as the rest of the fly.
• Tungsten-bead nymphs use the higher density of tungsten to gain more weight in a compact bead, making them useful in faster or deeper water.
• Egg patterns imitate fish eggs rather than an insect stage. They belong to the subsurface selection but should be chosen and fished as a separate food form.

Imitative and suggestive nymphs

Pheasant-tail, hare's-ear, caddis, stonefly, scud and perdigon-style patterns do not all behave in the same way. Some emphasise recognisable anatomy and texture; others use a slim outline, rapid sink rate or a small hotspot to suggest several food items. Use the product name and image to identify the family, but let the water determine weight and size.

River presentation

A natural drift requires the leader and line to move without pulling the flies out of their path. Short-line contact methods provide direct control, while an indicator or dry-dropper arrangement can suspend lighter patterns where permitted. In every method, maintain enough contact to recognise a pause without making the nymphs travel unnaturally.

Stillwater presentation

Nymphs can be suspended, allowed to descend, retrieved slowly or moved in short lifts. Count-down time and retrieve speed make depth repeatable. Watch for changes in line tension: stillwater takes are not always forceful.

How to make a useful change

If a plausible nymph produces no response, adjust depth first. Then change size or sink rate, followed by silhouette and colour. Altering one variable at a time provides information; changing the whole cast after every drift makes it difficult to identify what the fish preferred.