Much mystique has been built up about dry fly fishing over the years, but hatches of fly are less likely to be dominated by just one species than they were a hundred years ago, and the fish (thanks to hatchery breeding) are more catholic in their diet anyway. However, there is still a lot to be said for the challenge of pursuing trout with a dry fly which has been carefully chosen to match the hatching flies, although it can be argued that skilful, accurate presentation counts for more than precise fly selection.
You have to put in a lot of effort to learn fly fishing to be a good fly fisher. There are many factors which can affect your chances of a catch. For instance, most of the bigger fish in the water didn’t get that way by being easily hoodwinked by anglers’ flies; it always pays to have an eye for color and size and to know the times of the season, or the day, when a specific species of fly might hatch. Also remember that fish will sometimes feed more greedily on one species of fly than another. Other factors to take into account include the direction and quality of the light and its effect on fish vision, and the more subtle effects of drag, often undetected by you but not by the fish you hope to delude.
Most times on running water you should try to cast upstream to the rising fish. This will ease your problem of remaining unobserved and help place your fly over the fish without instant drag being induced to scare it away.
It often pays not to cast too far upstream of the fish, for the simple reason that there is then more time for drag to be induced before the fly gets into the taking zone. When fish prove very difficult it’s sometimes a good plan to cast into the receding ripples from a previous rise. This requires great accuracy and dexterity, but it will often get you a fish which is now taking on impulse, before it’s had time to give the fly or its movement some critical examination.
This method will often work wonders when there is more than one fish in the same taking position. This is when greed comes first, and in a mad dash to get the fly first, the fish will often throw all caution to the winds.
Most times, of course, a large trout in a stream will occupy its own well-defended territory and will seek to drive off other small fry or fish which try to intrude. Trout born and accustomed to life in the wild are essentially very territorial creatures. Those with hatchery origins, which spent a lengthy period being pampered with artificial feeding, tend to form into schools at first rather than establish territories, and it may be some time after their release into the wild before they abandon this habit.
In the clear chalk streams, a territorial trout can easily be identified as it cruises up and down its pitch sipping in the hatching duns. Chalk streams, because of their origins, are much more alkaline than rain-fed rivers. As a result, they have abundant weed growth which harbors a large number of natural insects, and for this reason the chalk stream trout are invariably larger than other river trout and much easier to see.
Trout which have got used to the plentiful supply of food in a chalk stream can be very selective in their feeding habits, but so, too, can fish in other waters. So being able to recognize the natural flies and choose an artificial to match them is a good skill that is essential to learn fly fishing.
Although it’s usually best to catch a dry fly upstream when fishing running water, there’s nothing to stop you casting it across or downstream if you prefer. However, if you do this, there’s more chance of your being seen, and of imparting drag to the fly before the fish has time to intercept it. If you do cast downstream, try to cast a slack line which may, for a few seconds, present your fly well without any drag. It will also avoid covering the fish with your leader.
You can practice and learn fly fishing on flowing water, but it may also be used to good effect on still waters. Here the technique is merely to cast the fly out and wait hopefully for a cruising fish to come and take it, sometimes giving the fly an occasional twitch to attract the fish’s attention. But the use of the dry fly is essentially a tactic for the chalk streams or those rivers with only a modest rate of flow, where it provides one of the most exciting of all forms of trout fishing.