Posts Tagged ‘Corixa’

Lockdown Fly Tying Day #19

April 14, 2020

This is a direct excerpt from my book “Guide Flies”, not only is it the story of an exceptional stillwater pattern, particularly for the bank angler, but equally a tale of the evolution of a pattern and the processes which took a basic fly from something of a concept to a simple and functional pattern over time.

The quick sink Corixa:
I first read about Corixa in Brian Clarke’s book “In Pursuit of Stillwater Trout”, a wonderful introduction to logical Stillwater bank fishing and recommended if you can get your hands on a copy. I can’t say that I took a whole lot of notice of this particular bug at the time, I had never seen a corixa and I seemed to catching enough trout on midges and hare’s ear nymphs to really worry about it.

Brian Clarke’s book ” In Pursuit of Stillwater Trout” has probably had a greater impact on my stillwater fishing than anything else I have read. A simple approach based on understanding and trying to copy real trout food items. The corixa pattern in the book isn’t what I would consider a great one, but the seeds for experimentation were planted.

I should digress for a moment and say that Corixa and Backswimmers are technically different, but they have very similar behaviours and profiles such that from a fly tying perspective you can pretty much treat them as the same, although this might annoy the biologists a bit.

Backswimmers in the water orientate themselves upside down when swimming, that said, from an angling perspective they are so similar to corixa that one doesn’t really need a separate pattern.

Corixa are aquatic beetles, of the family Corixidae, they don’t breath through gills as do mayfly nymphs, damselfly nymphs, dragonfly nymphs etc. but have to come up to the surface for air, remarkably they can also fly and do so on occasion to locate a partner and mate generally in large swarms. When they surface they trap the air in hairs around their bodies and carry it around with them rather like a miniature aqualung. They are of interest to anglers for a number of reasons:

Firstly they are found in an awful lot of waters that are also inhabited by trout.

Secondly they are there all year around and there is no messing about with pupal, nymphal, larval and other stages as with so much other trout food, which should at least make them easy to copy.

Corixa have no pupal, nymphal or other stages to concern the angler and if they are present in a water they are present all the time, something worth knowing if you are choosing a suitable pattern to start off with on a new water.

Pretty much there are just little corixa and bigger ones, although they don’t actually attain any really great size.

Thirdly, except when they are undergoing some mating flight they tend to occur somewhat randomly and as a result represent a rather opportunistic snack for the average Stillwater trout, you don’t need a “corixa hatch” to make good use of a suitable imitation.
Added to all of that, the corixa’s lifestyle make them a rather good target for trout and equally a good insect for bank anglers to imitate. Given their need to leave their weedy homes for a breath on a regular basis they put themselves at risk of detection and consumption all day long. When you imagine that a mayfly nymph only has to rise to the surface once in its lifetime, the poor corixa has to do this over and over again every single day.

Plus, because of the need for air and the swim required to fetch some they tend to inhabit relatively shallow water, well within the casting range of the average fly fisherman, which if you are an angler is a very fortunate happenstance.
The true importance of this humble little, if rather extraordinary, bug was brought home to me years ago when I had access to some spectacular fishing on private club water in the Kouebokkeveld a few hours drive from my home in Cape Town.

The area is arid, high and frigid (The name in Afrikaans means “Cold Buck Land” in direct translation). The small to medium sized dams, which are used by the farmers for irrigation of some of the most productive soft fruit orchards in the world, make excellent trout habitat in a country where a lot of the water is just too warm.
These dams regularly produced, from simple fingerling stockings, some absolutely astounding growth and trout up to ten pounds were hardly out of the ordinary, the waters were also for the most part clear and weedy, ideal habitat for both fish and fishermen.

A corixa underwater, the tell tale shimmer of the trapped air around its body can be clearly seen.

Although most of these lakes sported populations of corixa, one in particular, and a favourite of mine, was absolutely filled to the brim with the little bugs. In fact it was almost impossible to put your hand in to pick up a sip to drink on a hot day without taking in more protein than you had bargained for. It became apparent over time that the trout tended to come into the shallows to feed, either early morning or late evening, when the light levels made them feel safer. They would on occasion do the same if there was a good riffle on the surface, one imagines for the same reason that they felt less vulnerable under those conditions.

When I first seriously started experimenting with corixa patterns most South African stillwater anglers were predominantly using large lures or general attractor patterns.

At the time most anglers were fishing woolly buggers or perhaps damselfly and hare’s ear nymphs, many on sinking lines. Having come from a different background fishing in the waters of the UK I had a somewhat alternative approach to bank fishing and didn’t even own a sinking line at the time. I preferred to fish a long leader and a single fly with a floating fly line that I could use to detect the takes of fish that were subtle when retrieving slowly.

Standing in the shallows fishing damsels and hare’s ears I came to think that the fish must eat the corixa, and although we rarely killed a fish when we did so it proved that they were stuffed to the gills with these little beetles. So much so that gutting a recently captured trout would on autopsy reveal something akin to a corixa sausage, with decomposing bodies at one end and still wriggling ones at the other. There were just so many of these bugs about that I seriously wondered if the trout had to feed for more than a few hours a day before they were left groaning on the bottom of the lake with indigestion. Certainly there were frequently very quiet spells in the fishing during midday.

Another image of a subsurface corixa clearly showing the “aqualung” of air trapped around its body.

So I set about testing some imitations of corixa, they are simple on the one hand but tricky to get quite right on the other. Trying to imitate the flattened and rounded body of the natural can easily result in too much material on a small hook. Most of the corixa found in this dam were no larger than a size 14. The key triggers it would seem are the silver bubble of air around the body of the insect, the flattened shape and the two paddles with which they propel themselves through the water. I am a great believer in trying to capture the key points of an insect when designing an artificial, a sort of caricature as it were of the real thing.

There were a lot of corixa patterns around at the time, some seemed better than others but to my mind they were never quite right. Many sported hackles as imitation of the legs, but corixa legs are quite pronounced and fine fibres of a hackle didn’t really seem to look right to my eye. Then other patterns of the day had two distinct legs manufactured out of one thing or another, the problem was that they were tied in separately, making for an additional operation at the vice and taking up more space than there really was available on the hook.

Using fibres from the back removes the need or adding additional materials and thus bulk of the fly. In my pattern I use two fibres glued together for each leg.

Eventually over a season or so of experimentation the “Quick Sink Corixa” evolved. Although on occasion we wanted a fly that didn’t sink too much for the most we wanted a pattern that would get down, at least a bit. The use of lead wire on the shank solved that problem but was the wrong shape and closed the gape of the hooks. By flattening the wire we suddenly solved the problem of the weight and the shape at the same time. This brought with it another problem however; traditionally one used flat silver mylar to imitate the reflective qualities of the air bubble around the body.

It certainly looked the part but it was terribly difficult to wrap flat mylar around the now squashed lead underbody. Eventually though we found that using a small bunch of silver or pearl crystal flash made wrapping the body much easier, even more so if you anointed the lead with a spot of super glue before you wound it on. The final revelation, and perhaps the most significant in this pattern was using pheasant tail fibres for the shell back, not that that is particularly unusual, but we realised that we could use the same material for the legs. Separating out two fibres on either side, after forming the back, we could cut out the excess and have neat legs, perfectly positioned on either side of the fly without any additional bulk and leaving space for a neat whip finish.

Of course this didn’t all happen overnight, we manufactured some good and some pretty dreadful and time consuming corixa imitations, I think that they all worked, but this pattern was the culmination of experiments and adjustments which have now resulted in a quick to tie, neat, inexpensive and very productive Stillwater fly.

There was one further discovery about this pattern, I try to use ring eyed hooks for many imitative Stillwater patterns, if you don’t your lovingly created imitation of a damsel fly for example flips upside down every time you retrieve. Because we were fishing the corixa in such clear water we were able to observe the behaviour of the fly and noticed something very interesting. With each retrieve the fly would flip upside down for a moment, but it seemed that where the corixa is concerned this is a good thing. The fly on each slow strip gives a little semaphore flash of its underside, a little winking beacon that seemed to pull the trout in from yards away. So now the corixa is the one fly that I always tie on a down eyed hook, it just seems to enhance the effectiveness of the pattern a little bit.

Whilst for many patterns the fact that down-eyed hooks flip the fly over may be a disadvantage, in this corixa pattern it is a definite plus. Adding a little blink of flash on each retrieve, often pulling in fish from some distance.


Tying the Quick Sink Corixa:


This post and the fly described comes from my book “Guide Flies” if you would like to purchase a downloadable copy of it or my other book “Essential Fly Tying Techniques” you will find both links and discount codes below. The discount code will let you purchase the book at a 50% discount during lock down.

Discount code Essential Fly Tying Techniques: DR62J Code will expire 17 April 2020

Discount code Guide Flies : SB94S Code will expire 17 April 2020

Thanks for reading, stay safe out there.

I Fish, Therefore I Am

May 30, 2012

How Small a Trouth Every Day in May Challenge Fish Philosophy.

“I Fish, Therefore I Am”

The T shirt or bumper sticker bastardisation of Descartes’s famous philosophy “I think therefore I am” has I am sure been seen by most of us somewhere. The rather flip comment suggesting that without fishing we therefore don’t exist. Of course we would still exist if we stopped fishing or there were no more fish. You would still be able to see yourself in the mirror and would still have legs and arms, fingers and toes so existence in the sense of still being here a living breathing human being. Yes you would still exist, but would it be the same you?

I don’t think that I would exist as the same me without going fishing, it is far too intertwined with who I am and what I do, in essence I suppose it defines me. It is my job, I write about it and discuss it, most of my friends come from fishing circles , so without it, much of that would fall away and the “me” which is “me” now, wouldn’t be “me” anymore.

In Descartes’s discussion he essentially suggests that if he can create a new reality where nothing actually exists and can then think about the fact that nothing exists then by definition he must at least himself exist. The act of thinking proving that his presence is real.

Which leads to an interesting thought, how much of fishing is real, or is it simply an illusion. Much of what we have taken to be true frequently proves to be untrue but at the same time is that material?

For example I recall years back fishing a glorious trout dam in the cool days of an early winter. The water was chilly and the wind was blowing a gale. The general modus operandi at the time was to fish floating lines from the bank, the wind behind one to keep contact and help detect the subtle takes of the trout in the shallows. But it so happened that my hat blew off and I thought that I should wait until it was halfway across the dam and then commence a walk around the shores to retrieve it.

On reaching the far shore my hat was bobbing in the waves, rather serious waves as it turned out, the reach across the dam allowing the wind to generate no small amount of frigid surf. The edges of the dam were becoming muddied as a result of the wave action and it was so windy as to make casting near impossible, which was why we hadn’t fished this shore. Still I was standing there, newly retrieved and soaking hat, wet and chill on my head and I figured that I may as well make a cast or two despite the conditions.

To have any hope at all I walked out to a point where the waves were near breaking over the tops of my waders and heaved what line I could manage into the maelstrom of surf. The line stopped in the air and swung back at me, about the best I could manage was to fish along the shore, the flies level with my standing position pretty much fishing just along the shoreline.

Watching for takes was very tricky but didn’t the line seem to straighten up for a moment? I struck and was latched onto a very lively rainbow of about four pounds on a corixa pattern of my own design. A good start on the very first cast in the new position.

Another cast into the gale and another fish of similar size, then another and another. I think that I caught six fish in almost as many casts and confidence had soared “knowing” that the fish were in the shallows, under the protective cover of the slightly murky water and the spume of the crashing waves. The water was filled with broken weeds and all manner of flotsam as obviously the wind concentrated food in the bay I was fishing. I was quite sure that this was knocking the corixa out of the weeds and making them easy prey for the fish. Now it is unusual for me to do so but on this occasion I killed one of the fish to take home for supper.

When I finally arrived home I cleaned the fish and was amazed to find that its stomach was completely filled with tiny green bloodworms of exactly the same hue as the weeds, not a corixa in sight. How on earth the fish could pick out these tiny camouflaged morsels in the soup of that shoreline I have no idea. More to the point, my hypothesis that the fish were feeding on the corixas was quite apparently erroneous, although equally obvious was the fact that despite working on the incorrect premise I had still been successful.

Sometimes then one can have the wrong philosophy and still prevail, in fishing perhaps that happens a lot more than we would care to imagine. My primary philosophy when fishing is to practise catch and release. Generally viewed as a good way to be for the benefit of the trout and ultimately for the angler. But the hidden benefit is that if you don’t actually go and kill the fish you don’t know what they were really eating and then can bathe in your own sense of self-importance without risk of being proved a fortunate fool. Of course there are stomach pumps which can equally reveal the truth without the demise of the trout. But I tend to shun those because perhaps the best philosophy when fishing is “what you don’t know can’t hurt you”.


May 22, 2012


How Small a Trout Every Day in May Challenge.

According to Wikipedia runoff occurs when the soil is saturated to capacity and excess water from rain or snowmelt then flows over the land. Ultimately finding its way into channels, streams, rivers and the sea.

What that means to fly anglers in these parts is that the first rains of autumn don’t do a whole lot to the water levels, the streams stay clear and perhaps rise an inch or two. In our environment at the end of a long, hot and dry summer it offers relief to both fish and angler alike. Cooler water and a little more current to bring food to the trout and to better disguise the errant presentation by the fly fisher.

It can provide some of the best fishing of the year. It is the next big rains which put the kibosh on the fishing. With the ground already saturated (if you are of scientific bent limiting the soil’s “infiltration capacity”), the water runs off all the faster producing a rapid increase in flows in the streams and frequently changing the fishing from a delicate operation with tiny dries to an inelegant struggle with tungsten beaded nymphs and the accompanying risk of drowning.

Mind you understanding a little of the dynamics can help one locate fishing right up to the end of the fishing season if you keep your wits about you.

Hereabouts there is one stream with a dam near its source, what overseas anglers may refer to as a “tail-water fishery”. Unfortunately it doesn’t produce the massive trout of some of its more famous international brethren but it does offer a buffer to that sudden onset of runoff water. The dam acting as a capacitor holds back the increased flows and the stream below it therefore may offer fishing when the alternatives are blown out.

Most of our streams flow through sandstone gorges, unaffected by agriculture and as such rarely suffer the siltation and discolouration of those flowing through arable land. Fortunately we don’t have to deal with much by way of the influx of sediment or agrichemicals because the rivers are too remote. This isn’t the case in a lot of other rivers where that runoff can stop fishing operations for days if not weeks.

I recall with great fondness a dam we used to fish in the winter months up in the Kouebokkeveld, a highland plateau which would get tremendously chilly at the onset of winter. (Kouebokkeveld, for the uninitiated actually means Cold Buck Land and snow and ice along the dam’s edges wasn’t uncommon”)

The water, referred to as Luciano’s as much to disguise it when chatting in public as anything else lay in a shallow valley in a chain of farm dams used primarily for irrigation. The water would in early winter be crystal clear and freezing cold and the trout in it would grow to enormous size on a diet of tadpoles and corixa. The lake in fact had the most prolific numbers of these tiny subaquatic beetles I have ever seen and they represented a massive food source for the fish.

Standard operating procedure was to make the two plus hour at the commencement of winter, just about the same time that the rivers were going into flood. The cold weather would increase the activity of the fish and at the same time their fighting spirit which would change from week to week as the temperatures dropped It was key to be there early, in the frigid pre-dawn to intercept fish averaging six to eight pounds, feeding in the shallows and hunting those tiny bugs in the margins. They didn’t like coming close during the day, the clear shallow water making them very nervous so one had to be up well before first light and rig up breath steaming in the headlights of the car.

Frequently we would be tying knots in the glow of the lights only to run around the back to warm frigid fingers in the exhaust and regain some feeling in our extremities. But if you got your timing right you would find fishing that was out of this world. Hooking massive trout on #14 corixa patterns without more than the leader in the water and watching the backs of the fish break the surface behind one’s fly was a rush of pure adrenaline. The fish, hooked in such shallow water would go berserk stripping line from the reel like bonefish as they raced towards the middle of the lake. It was in short some of the most exciting stillwater fishing you might ever hope to enjoy.

As winter progressed the fishing would get better and better and we would make the journey most weekends knowing full well that it was going to come to an abrupt halt at some point and that there was no telling when.

What would happen was that as winter progressed and the rains fell unabated the feeders would muddy up and fill the dams higher in the valley.  Once they were full the overflow would pour into the last one in the chain and the lake would turn to chocolate virtually overnight. You just didn’t know exactly at what point that would occur and each trip would be filled with both excitement and trepidation that it could be the last.

Eventually one would arrive in the dark, rig up the corixas and position oneself along the margins, making the odd exploratory cast. It would initially be too dark to see and one fished on faith. As the sun rose, generally at this point glistening off the sparkling and heavily frosted grass reality would dawn. The water had turned to the colour of cocoa and all normal fishing was over for the remainder of the year, the window of opportunity slammed shut by the runoff from higher in the valley.

That dam is no longer worth fishing, it was drained dry at some point and the fish and food chain lost, but I still have glorious memories of fishing there and the bitter sweet expectation of a long drive in foul weather, never knowing if you were to be casting into gin or chocolate on arrival.