All natural foods upon which trout feed - such as aquatic and terrestrial insects, minnows, worms, crustaceans, shellfish, amphibians, rodents and reptiles - can be imitated by today's fly tying materials. ("Guide to Aquatic Foods", Dave Whitlock 1982).

Whitlock points out that fly fisherman and fly tiers often loosely use the descriptive terms of suggestive, impressionistic, realistic, and exact to describe the concept of artificial imitations in relation to their natural trout foods. He, for the sake of clarity, defines the terms in his writings. lecturing and fly tying:

  • Suggestive - a particular form of artificial fly that depicts a simple, crude, almost nondescript live natural food.
  • Impressionistic - a particular form of artificial fly that gives a more distinct illusion of a general food form, such as a snail, mayfly nymph, or sculpin minnow.
  • Realistic - a particular form of artificial fly that more closely imitates a particular live species in which the major imitation characteristics - size, shape, color, and texture - are observed.
  • Exact- a particular form of artificial imitation that seeks to duplicate an existing aquatic food by being its best possible copy.

<1--end info1-->

Five Major Elements of Imitation

Whitlock goes on to describe the five major characteristics of imitation:

  • Size - The length, width, and thickness of a natural aquatic food or the imitation of this food. Generally, the exact length is most important to imitate with the smallest foods (1/8" to 1/2"), then width and thickness becomes more important as overall size increases (over 1/2"
  • Action - The movementor degree of movement of a natural or imiation including its own muscular movement and what the water or entrapmenton the water gives it. The imitation whenfished is givenproper live imitative action by the angler' manipulation of cast, rod,line, leader, general design or shape of imitation and water's movement, vulnerability and proper attitude of the imitation to a trout.
  • Texture - The overall feel, softness or rigidity, of a natural or imitation. Each natural food has a particular identifiable texture or feel when touched or bitten by a trout. So an imitation of such foods should have this same general feel. The tyinjg material considered or used for an imitation should be chosen withthe same feel or texture. Very hard or very soft imitations seldom fall into this realistic texture range.
  • Shape - The overall outline or silhouette of an aquatic trout food within three dimensional size. Shape should be considered closely when fly imitatn designing is done. The best or most versatile imitations usually have the more impressionistic shapes which give the idea of many possible aquatic trout foods.
  • Color - Natural aquatic trout foods have distinctive shades and tones of many colors. Normally exact duplication of chroma or color is not necessary becasue even within a common group of naturals there will be wide variations in shades and tones of these colors. Imitations usually are effective if they generally color pattern imitative.