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The Black Fly Challenge – a postscript. Ed Herbst writes:

Sunday, 26 October 2014 17:35

The first field tests of the Simulid nymph – an imitation of the ubiquitous Black Fly larvae - have indicated that it is a promising pattern. In its current form it consists of four materials, black thread,  a metal or glass bead, fine black wire and UV light-cured resin tied on a #16 hook

Here are three feedback reports and a significant factor seems to be the gleam of light through the clear sections of the fly.

Click in images to enlarge

2 Simulid Nymph A

An underwater photograph showing how the light is reflected through the clear sections of the fly. Tom Sutcliffe photo


Andrew Ingram – Elandspad beat 2

Apart from a stiff downstream breeze on the Elandspad conditions were perfect. As there was no obvious movement of fish I decided to start  fishing with the size 16 Black-fly nymph made for me by Ed. The first cast gave me my length and second was placed in a bubble line and in an instant my first fish of the season was on. From there things happened fast.  Every couple of casts produced a fish, one which was blind in one eye!

1 Ingram blind trout

About an hour later the fly, tied on with 7X tippet, was taken by possibly the biggest rainbow that I have seen on the Elandspad and after half a dozen cartwheels out of the water the knot gave and the fish kept the fly. After that I tried Ed’s #16 green and then red brassies for about an hour  … no luck … and so decided to risk the second and last black fly nymph.  Two fish later it was also broken off …

Tom Sutcliffe - Lourens

We were on a low, gin clear mountain stream above Lourensford farm in Somerset West. Robin Douglas was using a small Para-RAB and I stuck with the Ed’s nymph, both of us on a metre-plus of 7X tippet.

The first thing that struck me is that the glass bead version sinks really fast given its totally smooth surface,  but in the fine flow the tungsten bead version tended to hang up a lot on stones. Then I also noticed that the pitch black fly was easy to follow in the drift, of course other than when I placed it in  the fast, white water at the head of runs. This is where I thought I’d get most of my takes, given that the naturals prefer fast water. But I was wrong. The fly did best in the smooth-surfaced glides and tail outs.

There were two notable fish. The first was a trout I saw swing at least a metre to grab the fly. The second was a trout hanging well back in the smooth, crystalline flow at the tail of a wide pool. He was swinging side to side as he fed, looking as light as a feather in the water and it really was a beautiful thing to watch. I unhooked Ed’s nymph, stepped to one side to get a better line on the fish, slipped and went in with a splash. I got up cautiously, looked for the fish, and saw he was still feeding!

I threw a cast that dropped the fly ahead and to the right of fish and in a second the current had swept the fly past him. But the fish swung around and chased the fly at least two metres, took it and I hooked him.

At the end of the day I guess the scores between the Para-RAB and Ed’s nymph were about even, but this little pattern shows serious promise.


6 Simulid Nymph D

A Deon Stamer net provides the backdrop to one of the two trout which chased the Simulid Nymph downstream (Tom Sutcliffe photo)


Robin Douglas - Lourens

We’d fished for about three hours and on approaching the penultimate pool on the beat, I noticed a trout feeding strongly in the tail of the pool. Tom quickly spotted it and commenced the stalk. He had his eyes firmly locked onto the fish and consequently took a tumble into the stream. Tom never missed a beat though and soaking wet, with his eye still firmly locked onto the feeding fish said, “I’m going to catch him for you Robin”. This was a difficult fish to cast to as it was sitting right at the tail of the pool in very clear and calm water. I was convinced Tom would line him but the cast was perfect. The fish turned and followed the fly, decided it did not want it and swam back to its station. Then it changed its mind, decided that it definitely DID want that fly, raced after it and ate it. I cannot remember when I have enjoyed the catching of a trout more. Nymph fishing at its best.


My first attempts to imitate the Black Fly larvae involved a 1.5 mm tungsten bead in black and Hends ultra-fine flat lead for the body.  This proved too heavy for Western Cape streams and, also, although the flat lead required less wraps than wire and was easier to break, the resulting fly was too opaque.

I now tie two versions – one with a black brass 1.5 mm bead sourced from Frontier Fly Fishing in Johannesburg. This is tied on the Grip 11011 BL hook which seems identical to the Tiemco 103BL. Brass is two and a half times lighter than tungsten making it ideal for early spring conditions in the Western Cape. The tungsten and lead version on a nymph hook would be better suited for yellowfish.

The second version is tied with a black 14/0 glass bead for the low water conditions which prevail in summer and early autumn on our streams. To distinguish it from the metal version I tie it on a #17 Tiemco 102Y hook – also sourced from Frontier - which has a microbarb. A glass bead has a cylindrical hole, unlike the countersunk metal beads and this bead slips easily over the microbarb.

To start tying the fly, hold the hook by the eye in a hackle plier and place the bead in your palm. This facilitates getting the bead onto the hook.

At the hook eye, tie a tapered cone of black thread and whip finish. Push the bead against it. This helps avoid getting the UV resin into the hook eye.

Tie a similar cone of thread at the rear of the bead and whip finish. This, when covered with resin, mimics the tapered abdomen of the larva.

Place a thin layer of super glue on the hook shank and wind fine wire in narrowly spaced turns from the hook bend to the back of the thread/bead cone. This anchors the wire and makes it easy to break off. By leaving gaps between the wire wraps you create a more variegated colour and make the fly less opaque.

At the bend tie a smaller blob of black thread to mimic the head of the insect and whip finish.

Cover the fly with resin creating the Coke bottle shape and cure with the UV light.

Tom Sutcliffe says that the light transmitted through the clear sections of resin is a striking feature of the pattern.

4 Simulid Nymph C

In later versions, a gap is left between the wire wraps improving the colour variegation and making the fly less opaque. Tom Sutcliffe photo

This could well be a supernormal stimulus as described by Dutch biologist Niko Tinbergen



I am currently reading an outstanding new book, Presentation Fly Fishing, by Jeremy Lucas. Jeremy is strongly influenced by competition techniques. He makes the point that using small nymphs, #18 – 22, pays dividends and that these nymphs should be smooth and streamlined to improve water entry. To this end natural materials like pheasant tail fibres and hare’s ear fur have been replaced by metal nymphs coated with thermo-setting ceramic pains such as Dala which is available locally.



There is a good video of this technique on Jean-Paul Dessaigne’s outstanding website


The Simulid Nymph is outstanding in this regard. It is very streamlined, presents delicately and is a lot quicker and easier to tie than the ceramic nymphs – a proficient tyer would probably take about three minutes.

3 Simulid Nymph B

In direct rather than reflected light, the distinctive shape of the Simulid Nymph is emphasised. Tom Sutcliffe photo.

Black Fly life cycle

The life cycle of the black fly from egg-laying to emergence is around three weeks and in the Western Cape there is a massive peak in early spring.

Breeding occurs throughout the year however and we probably have about six generations a year

As far as behavioural drift is concerned, Black Fly seem to be more important than Baetis nymphs according to the Blue Quill Angler website:

In a recent study, black flies were consistently consumed by trout at a much higher rate than their proportion in the drift. While Blackflies composed about 10% of the drift, they made up nearly 70% of the trout diets in June and July! (The American summer).

If that isn’t enough for you, consider that on the same stream, Baetis–the orthodox angler’s security blanket–made up 70% of the drift and contributed a mere 20% of the total trout diet while other common drifters Ephemerella (PMD) mayflies, were nearly unscathed.


Behavioural drift occurs at dusk and dawn with the major peak at dawn.

In this regard the Simulid Nymph should excel with its contrasting black and clear sections and the ability of the latter to transmit and reflect light.

5 Otters Simulid

Otters Blackfly Larva

Two commercial patterns available in the USA, the Otter’s Blackfly Larva by Dream Drift Flies and one by Steve Parrot which is marketed by Umqua recreate the Coke bottle shape of the natural but lack the translucency of this pattern.

7 Umqua black fly larva

Patterns by Umqua and Dream Drift Flies lack the translucency of the Simulid Nymph and its adaptability in terms of the weight afforded by the tungsten, brass or glass beads

You can read more about these patterns on the Planet Trout website


This is a follow up article from Ed's original piece on the subject at http://www.tomsutcliffe.co.za/fly-fishing/friend-s-articles/item/957-black-fly-%E2%80%93-the-challenge-by-ed-herbst.html 


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