Nymph (fishing)

An artificial fly or fly lure is a type of fishing lure, usually used in the sport of fly fishing (although they may also be used in other forms of angling). In general, artificial flies are an imitation of natural food sources which fly fishers present to their target species of fish while fly fishing. Artificial flies are constructed by fly tying, in which furs, feathers, thread or any of very many other materials are tied onto a fish hook. Artificial flies may be constructed to represent all manner of potential freshwater and saltwater fish prey to include aquatic and terrestrial insects, crustaceans, worms, baitfish, vegetation, flesh, spawn, small reptiles, amphibians, mammals and birds, etc. Effective artificial fly patterns are said to be killing flies because of their ability to put fish in the creel for the fly fisher. There are thousands of artificial fly patterns, many of them with descriptive and often idiosyncratic names.

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.

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Wikipedia