Fly tying is a common practice in fly fishing, considered by many anglers an important part of the fly fishing experience. Many fly fishers tie their own flies, either following patterns in books, natural insect examples, or using their own imagination. The technique involves attaching small pieces of feathers, animal fur, and other materials on a hook in order to make it attractive to fish. This is made by wrapping thread tightly around the hook and tying on the desired materials. A fly is sized according to the width of the hook gap; large or longer flies are tied on larger, thicker, and longer hooks. The construction of tube flies is different in that the tier secures materials a tube rather than to a hook. These flies are rigged by passing the fishing line through the tube before attaching a hook.
Generally, fly patterns are considered either "imitations" or "attractors". These can be further broken down into nymphs, terrestrials, dry flies, eggs, scuds, and streamers. Imitations seek to deceive fish through the lifelike imitation of insects on which the fish may feed. Imitators do not always have to be precisely realistic in appearance; they may derive their lifelike qualities when their fur or feathers are immersed in water and allowed to move in the current. Attractors, which are often brightly colored, seek to draw a strike by arousing an aggression response in the fish. Famous attractors are the Stimulator and Royal Wulff flies.
The first literary reference to flies and fishing with flies was in Ælian’s Natural History probably written about 200 A.D. That work discussed a Macedonian fly. The Treatyse on Fysshynge with an Angle was published (1496) within The Boke of St. Albans attributed to Dame Juliana Berners. The book contains, along with instructions on rod, line and hook making, dressings for different flies to use at different times of the year. Probably the first use of the term Artificial fly came in Izaac Walton's The Compleat Angler (1653),
Oh my good Master, this morning walk has been spent to my great pleasure and wonder: but I pray, when shall I have your direction how to make Artificial flyes, like to those that the Trout loves best?
The 1652 4th edition of John Dennys's The Secrets of Angling , first published in 1613, contains the first known illustration of an artificial fly.
By the early 19th century, the term artificial fly was being routinely used in angling literature much like this representative quote from Thomas Best's A Concise Treatise on the Art of Angling (1807) to refer to all types of flies used by fly fishers.
The art of artificial fly-fishing, certainly has the pre-eminence over the other various methods that are used to take fishes in the art of angling
Although the term fly was a reference to an imitation of some flying insect, by the mid-19th century the term fly was being applied to a far greater range of imitation.
The term fly is applied by sea fishermen to a certain arrangement of feathers, wax, etc., which I am about to describe the manufacture of, and which may be used with considerable success in mackerel, basse, and pollack fishing. I am not disposed to think, however, that such baits are ever mistaken by the fish which they are intended to capture for flies; but the number used, the way in which they are mounted, viz., several on one trace, and the method of their progress through the water, rather leads me to the belief that they are mistaken for a number of small fry, and treated accordingly.
A major concept in the sport of fly fishing is that the fly imitates some form of fish prey when presented to the fish by the angler. As aquatic insects such as Mayflies, Caddisflies and Stoneflies were the primary prey being imitated during the early developmental years of fly fishing, there were always differing schools of thought on how closely a fly needed to imitate the fish's prey.
In the mid to late 19th century, those schools of thought, at least for trout fishing were: the formalists (imitation matters) and the colourists (color matters most). Today, some flies are called attractor patterns because in theory, they do not resemble any specific prey, but instead attract strikes from fish. For instance, Charles Jardine, in his 2008 book "Flies, Ties and Techniques," speaks of imitators and attractors, categorizing the Royal Wulff as an attractor and the Elk Hair Caddis as an imitator, whereas "... in sea trout and steelhead fishing there is a combination of imitation and attraction involved in fly construction". Paul Schullery in American Fly Fishing - A History (1996) explains however that although much has been written about the imitation theories of fly design, all successful fly patterns must imitate something to the fish, and even a perfect imitation attracts strikes from fish. The huge range of fly patterns documented today for all sorts of target species-trout, salmon, bass and panfish, pike, saltwater, tropical exotics, etc. are not easily categorized as merely imitative, attractors or something else.
The categorization of artificial flies has evolved considerably in the last 200 years as writers, fly tiers and fishing equipment retailers expound and promote new ideas and techniques. Additionally, as the popularity of fly fishing expanded globally to new and exotic target species, new flies and genera of flies came into being. There are many subtypes in some of these categories especially as they apply to trout flies. As well, any given pattern of artificial fly might well fit into multiple categories depending on its intended use. The following categorization with illustrative examples is derived from the following major artificial fly merchants offerings.Orvis - An American Fly Fishing Retailer in business since 1856
Farlows of London - A British Fly Fishing Retailer in business since 1840
TheFlyStop - An online fly merchant since 2004
Umpqua Feather Merchants - An American artificial fly manufacturer and wholesaler in business since 1972
Dry flies are designed to be buoyant, or land softly on the surface of the water. Dry flies typically represent the adult form of an aquatic or terrestrial insect. Dry flies are generally considered freshwater flies.
Wet flies are designed to sink below the surface of the water. Wet flies have been tied in a wide variety of patterns to represent larvae, nymphs, pupa, drowned insects, baitfish and other underwater prey. Wet flies are generally considered freshwater flies.
Nymphs are designed to resemble the immature form of aquatic insects and small crustaceans. Nymph flies are generally considered freshwater flies.
Emergers are designed to resemble the not quite mature hatching aquatic insect as it leaving the water to become an adult insect. Emerger flies are generally considered freshwater trout flies.
Streamers are designed to resemble some form of baitfish or other large aquatic prey. Streamer flies may be patterned after both freshwater and saltwater prey species. Streamer flies are a very large and diverse category of flies as streamers are effective for almost any type of gamefish.
Terrestrials are designed to resemble non-aquatic insects, crustaceans and worms that could fall prey to feeding fish after being blown or falling onto the water.
Bass and panfish flies, bugs and poppers are generally designed to resemble both surface and sub-surface insect, crustacean, baitfish prey consumed by warm-water species such as Largemouth bass or bluegill. This genus of flies generally includes patterns that resemble small mammals, birds, amphibians or reptiles that may fall prey to fish, or in the case of panfish flies, small aquatic insects or crustaceans.
Pike and musky flies are generally designed to resemble both surface and sub-surface crustacean, baitfish prey consumed by species of the genus Esox such as Northern Pike or Muskellunge. This genus of flies are larger than bass flies and generally includes patterns that resemble baitfish and small mammals, birds, amphibians or reptiles that may fall prey to fish.
Although many flies from the standard trout repertoire can be successfully used to tempt various species of carp, particularly the common carp, a number of traditional patterns have been modified to make them more appealing to carp. One example would be Barry's Carp Fly, which resembles the familiar thorax-plus-tapered-abdomen structure of many nymphs, albeit in an enlarged and bushier format. Some flies have been designed specifically to target carp, usually to imitate the various vegetative sources of food that omnivorous carp feed on such as berries, seeds, and flowers that may fall into the water. This small niche of the fly fishing / fly tying world began to grow dramatically in size and legitimacy around 2010 as a hitherto underground movement started to go mainstream in the United States, leading to numerous innovations. Several of those, like the family of so-called "headstand" flies, represent the most significant departures from traditional freshwater designs in many years.
Salmon flies are a traditional class of flies tied specifically to fly fish for Atlantic Salmon. Some salmon flies may be classified as lures while others may be classified as dry flies, such as the bomber. Salmon flies are also tied in classic and contemporary patterns.
Steelhead and Pacific salmon flies are designed for catching anadromous steelhead trout and pacific salmon in western North American and Great Lakes rivers.
Egg flies are all designed to resemble the spawn of other fish that may be encountered in a river and consumed by the target species.
Flesh flies are designed to resemble the rotting flesh of pacific salmon encountered in a river and consumed by the target species.
Saltwater flies are a class of flies designed to represent a wide variety of inshore, offshore and estuarial saltwater baitfish, crustacean and other saltwater prey. Most of the time you see a pattern it will be represent a shrimp, crab, baitfish, or a combination of them. Saltwater flies generally are found in both sub-surface and surface patterns.
Bonefish flies are a special class of saltwater flies used to catch bonefish in shallow water. Bonefish flies generally resemble small crabs, shrimp or other crustaceans.
Tarpon flies are a special class of saltwater flies used to catch tarpon in both inshore and offshore waters. Tarpon flies generally represent small baitfish commonly preyed upon by tarpon.
Striped bass flies are a special class of freshwater-saltwater fly used to catch striped bass in freshwater, inshore and offshore waters. Striped bass flies generally represent small baitfish commonly preyed upon by striped bass.