The gypsy barbel in my local river are predominantly bottom feeders and they are well adapted to finding invertebrates in the mud and in and around the stones. I suspect that when they are in muddy stretches that it is senses other than eyesight that direct them towards their dinners. Because of this I nearly always use smallish nymphs to target them, generally tied on a size 14 hook and usually with a small tungsten bead.
Every now and then you may find a fish, or more usually a small group of fish taking dry flies from the surface and even when this is not happening you will see over the course of a few hours on the river that the odd fish will go up to take something from the surface even though such rises may be few and far between.
The “bugs” that fish take (and these include molluscs and crustaceans as well as insects) are either aquatic or terrestrial. The aquatic species grow up in rivers, hatch from or lay eggs in rivers or spend their whole lives scurrying over, or burrowing into the river substrate, hunting, grazing and even fishing with fine nets they make themselves. These are river residents whether full time or part time and a great deal has been written about them, particularly by trout fisherman.
But I have been wondering recently about the terrestrial species, the bugs that wind up in the river because of misfortune: being blown onto the surface or falling from overhanging vegetation or being swept from the grassy verges. What kind of things are they? How numerous are they? How big?
Outside on the terrace we have a swimming pool. If you live in the campo in Spain you pretty much need one of these as the summers are long and hot. It occurred to me that examining what had found its way into the pool would be a good way of knowing what kinds of bugs would be available to the barbel if they had a mind to feed from the surface. We keep the water chlorinated so that ALL the insects and bugs it contains are terrestrial in origin. The Guadalhorce fish of course would have the aquatic insects available also. On windy afternoons here bugs of many kinds as well as plant debris and pollen and dust and leaves all decide to take a dip in the pool. This afternoon I used a net to collect a sample of this stuff and dumped it into a plastic tray filled with water. When the leaves were removed I had a chance to examine my little bug collection.
I am no entomologist but it was clear that we had a few spiders, a house centipede, a bee, various moth-like insects, crane flies, small houseflies and ants. But a close look at the water surface of the pool showed that my little sample was vastly outnumbered by very tiny midge-like insects that were were lying on the surface film trapped there by surface tension. Another thing I noticed was that the black houseflies or very similar-looking insects seemed to have almost neutral buoyancy. If they penetrated the surface they drifted around at almost any depth in the water without any strong tendency to either float or to sink. This I thought was quite interesting because these were of a size that could be imitated by a simple black nymph.
My house lies in the same river valley as the Guadalhorce river and is only about three miles away as the crow flies and so it is probably fair to say that a collection of terrestrials very similar to the one I found today is being conveyed at this very moment by the river towards the Mediterranean.
Dry fly fishing is a relatively minor tactic on the Guadalhorce. It does have its day and perhaps I should do it more often. At this time of year the best fishing is in stronger flows and often the trick is to get something down to the bottom and let it trundle under the nose of a fish.
Of the bugs in my little sample taken today the best one to imitate is probably the black houseflies (I will take a punt here and suggest that they belong to the order diptera – but I know that people like Brian Jones reads this blog and he is far more knowledgeable about this subject and so I stand to be corrected).
My own standard “dry” is quite simple. It is tied with black dubbing and has a foam “wing” which gives it buoyancy. In the water it tends to float with the wing in the film and the rather untidy black body just beneath. The barbel seem to like it well enough on those occasions when they looking up and selecting from the smorgasbord drifting downstream above their heads. What is good to know is that, if the wing is trimmed back so that it no longer allows the fly to float, or I simply did not add enough foam in the first place, the slowly sinking fly also looks and behaves (as far as any dead thing can be said to “behave”!) just like the real thing.

Here is a sample of what the fish could choose. It occurs to me that many insects – particularly ants have very narrow “waists” and that their bodies are very clearly compartmentalised. I wonder if we imitate this well in general?

A few spiders were present. I have never heard of an imitation of a spider. The vast majority of the insects cannot really be seen in these photos. They were very tiny and liberally “sprinkled” across the surface of the pool.

For what it´s worth here are a couple of examples of the dries I use on the occasion that the barbel will take one. The body is dubbed and the foam is that stuff used in packaging of things like mobile phones. It is very thin and so I cut out strips and fold them over a couple of times before tying them in. I use thick thread to tie them in because thin thread can cut through. Once the wing is in place off goes the thicker thread and a thinner thread is used for the dubbing and to finish off the fly.