Choosing the right dry fly can sometimes seem more complicated than it needs to be. There are thousands of patterns available, often with only small differences in their colour, materials or construction.
The key is to understand **what the fish are feeding on, how the natural insects are behaving and how your artificial fly will appear on the water**.
In many situations, the size, silhouette and presentation of a dry fly are more important than its exact pattern or name.
## Start by Observing the Water
Before choosing a dry fly, take a few minutes to look at what is happening.
Are trout or grayling rising? Can you see insects drifting on the surface? Are there flies emerging, or are terrestrial insects being blown onto the water?
Look for clues such as:
- The size of insects on the water.
- Whether their wings are upright or lying flat.
- Their general colour and shape.
- Whether insects are drifting naturally or moving across the surface.
- Whether fish are taking insects from the surface or just beneath it.
If you can identify what the fish are feeding on, choosing an appropriate artificial becomes considerably easier.
However, even when you cannot identify the exact insect, these observations provide a useful starting point.
## Match the Size First
When trying to imitate natural insects, **size is often the first thing to get right**.
A trout feeding on small upwinged flies may ignore an artificial that is considerably larger, even if its colour and shape are otherwise convincing.
Likewise, a tiny dry fly may be a poor choice when fish are confidently taking large Mayflies.
You don't need to measure every insect precisely. Simply aim for a reasonable match in overall size.
It is often worth carrying a familiar pattern in several hook sizes rather than owning numerous different patterns in only one size.
## Consider the Silhouette
The silhouette is the outline of the fly as seen by the fish from beneath the surface.
This can be particularly important because fish are often looking upwards towards the light.
Different insects produce very different silhouettes.
For example:
- **Upwinged flies** generally have upright wings when resting on the surface.
- **Caddis or sedges** have wings that fold over the body in a tent-like shape.
- **Spent spinners** often lie flat on the water with their wings spread out.
- **Terrestrial insects** may present a broad, compact silhouette with legs extending across the surface.
Choosing a fly with the appropriate general shape can be more important than matching every detail of its dressing.
## Does Colour Matter?
Yes, although it is rarely the only consideration.
When imitating natural insects, try to match their general colour.
Olive, brown, grey, black and other subdued colours cover a wide range of insects encountered on UK rivers.
However, exact colour matching is not always necessary.
Lighting conditions, water clarity and the way a fly appears from beneath the surface can all influence how its colour is perceived.
If you have matched the approximate size and silhouette, small differences in shade are often less important than achieving a natural presentation.
## How Should the Fly Sit on the Water?
Not all dry flies sit in the same way.
Some are designed to float relatively high on the surface, supported by hackle, hair or buoyant materials.
Others sit lower, with their bodies resting in the surface film.
This difference can be important.
A fish feeding on insects lying low in the surface film may be reluctant to take a heavily hackled artificial riding high above the water.
Likewise, a buoyant, highly visible dry fly can be useful in broken water where a delicate, low-floating pattern would be difficult to see or keep afloat.
Think about how the natural insect is sitting on the water and choose a fly that behaves similarly.
## Choosing Dry Flies for Upwinged Hatches
Upwinged flies are particularly important to UK river trout and grayling fishing.
During a hatch, newly emerged adults may drift downstream while their wings dry before taking flight.
Traditional upright-wing and parachute dry flies can provide effective imitations.
Useful general patterns include:
- F-Fly.
- Parachute Adams.
- Olive Dun patterns.
- Iron Blue Dun patterns.
- CDC dry flies.
The appropriate size and colour will depend on the insects present.
If fish appear to be taking insects just beneath the surface rather than fully emerged adults, an emerger may be more effective than a conventional dry fly.
## Choosing Dry Flies for Caddis and Sedges
Caddis, commonly called sedges in the UK, are another important group of insects.
Adult sedges have distinctive wings that fold over the body, creating a tent-like profile.
Many are particularly active during the evening, although their activity varies between species.
Useful patterns include:
- Elk Hair Caddis.
- CDC Sedge.
- Deer Hair Sedge.
- General sedge imitations.
Unlike many upwinged flies, some adult sedges move actively across the surface.
A fly that can be skated or moved occasionally may therefore be effective when fish are chasing active insects.
However, when natural sedges are simply drifting, a natural, drag-free presentation may still be preferable.
## Choosing Dry Flies for Terrestrial Insects
Not all surface-feeding opportunities involve aquatic insects hatching.
During warmer weather, trout and grayling may feed on insects that fall or are blown onto the water.
These include:
- Hawthorn flies.
- Ants.
- Beetles.
- Daddy long legs.
- Other terrestrial insects.
Terrestrial patterns can be particularly effective beneath overhanging trees, along grassy banks and during windy conditions.
Unlike aquatic insects, their availability is often determined by what is happening on the surrounding land rather than by a hatch taking place in the water.
## Choosing a Dry Fly When Nothing Is Rising
You don't need to see fish rising before fishing a dry fly.
Fishing likely water with a dry fly is commonly called **prospecting** or **fishing the water**.
Rather than matching a specific hatch, choose a general pattern that fish are likely to recognise as food.
Useful choices might include:
- Parachute Adams.
- F-Fly.
- Griffiths Gnat.
- Elk Hair Caddis.
- General olive or brown dry flies.
- Suitable terrestrial patterns.
Look for areas where fish might be holding, such as current seams, pool tails, pocket water and the edges of overhanging vegetation.
A carefully presented dry fly can bring fish to the surface even when there is no obvious insect activity.
## Visibility Matters Too
A dry fly needs to be visible enough for the angler to follow it and recognise a take.
This can be difficult when fishing small patterns, particularly in broken water or poor light.
Some dry flies incorporate brightly coloured posts or other visible materials to help the angler track them.
Parachute patterns with coloured sight posts can be particularly useful.
The important thing is to balance visibility with an appropriate presentation.
A fly that you cannot see is difficult to fish effectively, regardless of how accurately it imitates the natural insect.
## Presentation Is Often More Important Than the Pattern
One of the most common mistakes in dry fly fishing is changing flies repeatedly when the real problem is presentation.
A trout may refuse a perfectly suitable fly because it is dragging unnaturally across the current.
Before changing patterns, consider:
- Is the fly drifting naturally?
- Is it passing through the fish's feeding area?
- Is the leader causing drag?
- Is the fly sitting correctly on the surface?
- Have repeated casts disturbed the fish?
Often, adjusting your position, changing the casting angle or improving the drift will make more difference than changing to another similar fly.
## What If a Fish Refuses Your Dry Fly?
A refusal occurs when a fish approaches or inspects your artificial but does not take it.
There are several possible explanations.
The fly may be too large, the wrong shape or sitting incorrectly in the surface film.
It may also be dragging slightly, even when the movement is difficult for the angler to detect.
If a fish repeatedly refuses your fly, first check the presentation.
If the drift appears natural, consider changing the size, silhouette or how the fly sits on the water.
Remember that a fish may also be feeding on emergers rather than fully developed adult insects.
## Do You Need Lots of Different Dry Flies?
No.
A modest selection of reliable dry flies in several sizes can cover a surprising number of fishing situations.
For general UK river trout and grayling fishing, it is useful to carry patterns representing:
- Small and medium upwinged flies.
- Larger Mayflies during their season.
- Adult sedges.
- Spent spinners.
- Terrestrial insects.
- General-purpose dry flies for prospecting.
As you become familiar with your local waters, you can add patterns that match the insects you encounter most frequently.
Understanding why you are choosing a particular fly is more useful than simply owning a large collection.
## Key Takeaways
- Observe the water and feeding fish before choosing a dry fly.
- Matching the approximate size of natural insects is often the best starting point.
- Silhouette and how the fly sits on the surface can be particularly important.
- Colour matters, but small differences in shade are often less important than presentation.
- Different dry flies imitate upwinged insects, sedges, spent spinners and terrestrial insects.
- Prospecting with a general dry fly can be effective even when no fish are visibly rising.
- Choose a fly that you can see well enough to fish effectively.
- Before changing patterns, check that your fly is drifting naturally.
- A small selection of proven patterns in useful sizes will cover many UK dry fly fishing situations.
In the next article, we'll look at **dry fly presentation and drag**, including why conflicting currents can make an artificial fly behave unnaturally and how to achieve a more convincing drift.
