Barbless Flies

Match The Hatch

The Blue-Winged Olive

All the information you need to help get the most from your Blue-Winged Olive 'Match The Hatch' selection of flies.

With the Trout season starting on the majority rivers throughout the UK in April, fly anglers thoughts switch from Grayling to Trout. One of the most common insects throughout the 'dry fly fishing year' in the UK is the Blue-Winged Olive.


The Blue Winged Olive (Serratella ignita) is a member of the Ephemerellidae family. Found in rivers across the whole of the UK, these flies are generally small with three long tails - it seems that the further north in the UK, the smaller the fly. The wings of the dun usually have a blue tinge to them - hence their name. We will learn more about the Ephemerellidae family through the season, as they make up lots of flies the angler is predominantly interested in.

Blue Winged Olives are commonly found in all rivers throughout the UK and Ireland. They can also be found in some of the smaller stillwaters, especially those which are fed by faster flowing streams. Blue Winged Olives prefer to live in fast-flowing streams and rivers, especially where abundant aquatic vegetation is present.

Blue-Winged Olive - Lifecycle

The Blue Winged Olive hatch usually starts in the first two weeks of June and will continue through until the end of August. It's also possible that you will see these flies on the water in May and September, but their main hatch is from June through August. Look out for these once the Mayfly hatch has finished. - when there are no Mayflies about use an Blue-Winged Olive imitation in late-May, then in September, try the Parachute version.

The Blue-Winged Olive's lifecycle is:

Nymph: A 'stone clinger' which rises to the surface to hatch.
Emerger: A prime candidate for trout food, the emerger breaks the water surface to transform into the Dun.
Dun: Hatches on the surface and pauses to dry its wings - a prime target for a hungry fish. At this stage the Blue Winged Olive has an light olive body and blue-ish wings - hence where the name comes from.
Spinner: After mating the Adult female will return to the water and lay her eggs in the more 'riffly' water. Once done, she dies and floats down stream 'spent' - the Spinner is the perfect imitation.

From a fly fishing perspective the stages which we must try to imitate are:

Nymphs - mornings until 2pm
Emergers - from noon to 3pm
Duns & Spinners - from noon to 4pm
Spent - from mid-afternoon until dusk

The Blue-Winged Olive hatch usually starts in late May/early June and is very prolific until the end of August/beginning of September.

Match The Hatch - Blue-Winged Olive Imitations

The most popular imitations for Blue-Winged Olives are any of the flies below (all contained within your 'Match The Hatch' selection), don't worry if you don't have these exact patterns, as anything which is in the general colour, profile and size will do. These flies should be fished as you would any other dry fly, the Blue-Winged Olive Upright being especially buoyant. These dry flies should be used as soon as you start to see the hatch appear (remember early hatches of Blue-Winged Olives don't last long), this can be anytime from 12:00 until 17:00, depending upon weather conditions.

The Blue-Winged Olive is a fly which is known for hatching in even the most inclement of weather, one of the only flies you can just about guarantee will hatch on your visit to the water in any month of the trout season. Outside of its normally hatch calendar the Blue-Winged Olive can still be found in the shady parts of the river.

BWO Nymph 2.png__PID:8bb24f8c-73ff-4247-a794-c249af4f0107

Blue-Winged Olive Nymph

Blue Winged Olive nymphs are small, thin and can be found clinging to moss covered stones (one of the many 'stone clinging nymphs') and vegetation around the riverbed where the trout can pick them off, sometimes they get washed off their stones and the trout hoover them up. The best imitation for these is the famous Sawyers Pheasant Tail Nymph (beaded when used in heavier flows). When imitating the Blue Winged Olive nymph, please take note of the body thickness, the body should be quite thin with a pronounced taper. Blue Winged Olive nymphs are roughly 10mm long and quite flat (just about the same as the nymph supplied).

Blue-Winged Olive Emerger

Try fishing this Blue-Winged Olive emerger with no fly dressing first. It will float for the first few casts and then it will slowly sink under the surface, this allows you to see which method works best and which the fish are interested in on that specific day. If you want your emerger to float high then use a powdered style floatant to keep it riding high on the water.

Don't be too afraid to let the pattern sink slowly and then manipulate it with your fly rod to help it rise through the water column, this perfectly imitates the emerging insect.

BWO Emerger 2.png__PID:4f8c73ff-5247-4794-8249-af4f01077e8b
Parachute BWO 2.png__PID:73ff5247-2794-4249-af4f-01077e8bce8d

Parachute Blue-Winged Olive

The Parachute style of Blue-Winged Olive you see here is tied to imitate the insect which has hatched and is resting on the surface, waiting for its wings to dry out - this is ideal for a trout to intercept it (as it cannot escape). Only fish this pattern (and the Blue-Winged Olive Upright below) once you can see fish rising.

When fishing with a parachute-style fly only apply floatant to the post, as you want the fly to fish in the surface film (not riding high on it like the Blue-Winged Olive Upright below).

Blue-Winged Olive Upright

An imitation of the Adult Blue-Winged Olive, this variant is fished dry and sits proud on the water surface. It can be used from early May, right through to the end of September.

Apply floatant to the full hackle, this allows the fly to stand on the water's surface with only the tips of the hackle making indentations on the surface - it is believed that the pattern of indentations is the trigger to the fish taking the fly.

BWO Upright 2.png__PID:52472794-c249-4f4f-8107-7e8bce8daef2
BWO Spinner 2.png__PID:2794c249-af4f-4107-be8b-ce8daef220e5

Blue-Winged Olive Spinner

Once the Blue-Winged Olive has returned to the water to lay its eggs, the females die and float on the surface, this is the spinner. The spinner is an easy target for Trout, and they can gorge on them in the early evenings. Just treat the wing and thorax to some floatant so the fly rides high on the water.

The best water to taget when fishing with spinners are the slower back eddies, as this is where fish partol looking for any insects which are trapped in the meniscus - they make easy pickings!

Blue-Winged Olive - Hatch Notes

When fishing with Olive imitations here are a few tips:

Nymphs - You need to present your chosen nymph as near to the bottom as possible - if you're not catching the bottom every now and then - you've not got your nymph deep enough!

Duns - When fishing any dun-style pattern, only apply floatant to the tips of the feathers near the eye of the hook. This will allow the fly to present correctly (just like the natural) on the water surface.

Dry Flies - As with all dry flies, correct application of floatant is the key when fishing these patterns. Only ever apply a gel/liquid floatant to the fly when it is fresh from your box and 100% dry (gel/liquids trap in moisture). Once your fly is wet, dry it with a cloth/amadou and then apply a powdered floatant to refresh it.

Spinner Patterns - When targeting Blue Winged Olives with 'spent' style patterns, always step up the thickness of your tapered leader & tippet (it's not uncommon to use 3X tapered leaders and 4X tippets). It can also help to use as short a length as possible. Spent patterns are designed with outstretched wings, and these act just like a helicopter rotor when you cast them and can easily twist your leader, so thicker and shorter is the name of the game.