Fly fishing is a distinct and ancient angling method, developed primarily for salmonids (trout and salmon, mostly) and now extended to other species such as pike, bass, and carp, as well as a wide range of marine species. Artificial flies are constructed — "tied" onto a hook with thread, fur, feathers and other materials — in sizes and colours to match naturally occurring food or simply to excite a fish. Fly rods are relatively light and long while the lines are relatively heavy, providing the casting weight. Lines may be tapered and of differing densities to float or sink and are matched to the rod according to weight. The fly itself can weigh very little and is normally attached to the line by a 2-3 meter leader which may taper to a very fine line at the tip end, also called the tippet. In fact, the main practical difference between fly fishing and casting is that in casting, you are using the weight of the lure to "throw" it out (much like throwing a baseball). In fly fishing, the "fly" is virtually weightless and you are using the weight of the line to place the fly where you want it to be. In fact, a fly line can be "cast" without any fly or lure on it at all, a feat impossible with a typical casting rod and reel. The point is that a fly can be presented gently and under the control of the angler instead of plopping down with a big splash. Stealth is often critical in fly fishing.

There are two basic forms of fly fishing, dry or wet. Dry flies are coated with a floatant and sit on the surface of the water. They are mostly cast upstream in moving water when fishing for trout. Wet flies are divided into other types such as nymphs, lures and true wet flies and they are all fished beneath the surface of the water.