Olive Upright

The Olive Upright (Rhithrogena semicolorata) is a member of the Heptageniidae family, a family of mayflies with over 500 described species. These flies are generally rather small with two long tails. The wings are usually clear with a blue-grey tinge to them. We will learn more about the Heptageniidae family through the season, as they make up the majority of flies the angler is predominantly interested in. The Olive Upright is a very close relative of the March Brown.

Where To Find Them

Olive Uprights are more commonly found on the larger rocky rivers in the north and south-west of England; throughout Scotland, Wales and Ireland.
Olive Uprights seem to prefer rocky or stony river beds with faster flowing water.

When To Find Them

The Olive Upright hatch usually starts in the first two weeks of May and will continue until mid-August.
During May to July hatches usually occur around midday and can last for up to three hours, with major bursts of activity only lasting around 15 to 30 minutes (have your flies ready before you enter the water!). Once we get into August the hatches tend to peter out quite quickly.


Olive Upright nymphs are small, thin and can be found clinging to 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 Olive Upright nymph, please take note of the body thickness, the body should be quite thick with a pronounced taper. Olive Upright nymphs are roughly 10mm long and quite flat (just about the same as a size 16 Pheasant Tail Nymph):

The Olive Upright'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 Olive Upright has an olive-brown body and blue-grey wings.
  • Spinner: After mating the Adult female will crawl down bank-side vegetation to lay her eggs, trout are not too interested in this stage.

Unusually for one of the mayfly family, trout don't seem too interested in Olive Upright spinners. From a fly fishing perspective the three stages which we must try to imitate are:

  • Nymph
  • Emerger
  • Dun (see above)


The most popular imitations for adult Olive Upright are either of the dry flies below (and especially the emerger), 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 Jingler being especially successful as it imitates a number of flies which all hatch at a similar time. These dry flies should be used as soon as you start to see the hatch appear (remember early hatches of Olive Uprights don't last long), this can be anytime from 12:00 until 15:00, depending upon weather conditions.

Emerger Imitations

Thorax Adams

Emerger Imitations

Once you start to see Olive Uprights coming off the water, try an emerger imitation:

Wyatt's Deer Hair Emerger

Nymph Imitations

If you are fishing in a morning or cannot see any signs of an Olive Upright hatch, then nymphs are the way to go, in early spring it is sometimes more productive to use a bigger nymph. Take a look at these for some inspiration:

Copper Head Mary

Red-Neck Pheasant Tailed Nymph

Always keep in mind how deep and how fast the water is when nymphing in early spring, that will tell you how heavy a nymph you need to use. All you need to remember when fishing nymphs in the early spring is that you need to be near (or on) the bottom, if you're not getting snagged up every so often, you're not fishing deep enough.

Image Source

Olive Upright Title Image: Courtesy of Mr D Southall - thanks Dave.


This email is brought to you with the sole intent to spread the information around so we can all maybe learn something. If you would like to buy any Olive Upright imitations for your upcoming forrays, we do hope that you will consider us and see what flies we have to offer. If you are considering any of the above flies, they can be found using these links:

Thorax Adams
Wyatt's Deer Hair Emerger
Pheasant Tail Mary
Red-Neck Pheasant Tailed Nymph