Feeding lies are places where fish go ONLY to feed. These lies are usually in shallow water. Feeding lies are most used in a hatch situation, but fish can be found watching for food in feeding lies during opportunistic periods as well. There is no shelter from predators available in these lies so fish in such places tend to be very "spooky".
Streams: Feeding lies are found in riffles less than knee deep, in calm water near banks (including those of islands and sandbars), in areas of smooth, low water, such as the tails of pools or behind large structures, and on the inside of bends. A feeding lie may also be just beneath the surface of a smooth, slow, deep area, such as an eddy.
Lakes: Feeding lies are in areas such as shallow, weed-less edges, in places like inlet deltas, and in the slicks preceding an out-fall. An especially popular feeding lie in many lakes is the cruising lane between beds of weeds and the shore. Fish can also be found cruising just under the surface over an entire lake when there are insects readily available.
Sheltering lies are areas where fish go ONLY to find protection from predators. Because of the relative lack of food in such places, fish usually do not hold in them for extended periods. Fish head to sheltering lies when alarmed or hooked, so in order to play a fish effectively, a fly fisher should scout out all probable sheltering lies before casting to a fish. Sheltering lies are always under something.
Streams: Riffles over waist deep and pools and rapids in which the fish have enough water over them to feel secure, are definite sheltering lies. Also, masses of weeds and other thick covering structure, such as dead falls, provide excellent shelter.
Lakes: The deep water of the middle, and any weedbeds or other submerged structure like stumps and big rocks, provide shelter for a spooked fish.
Prime lies are areas where fish can find both a steady flow of food and reasonable protection from predators and current at the SAME TIME. Prime lies often hold concentrations of fish. Identifying such places can be the difference between an OK day of fishing and a great day.
Streams: Riffles between knee and waist deep can be considered prime. The choppy confluence line between currents, such as where two channels of a river flow together or where an eddy meets the main flow, are excellent prime lies. Overhanging cover, be it willows or an undercut bank provide some of the best available lies, especially when terrestrials are prevalent. In addition, the deep side of drop-offs, waterfall plunge-pools, and the sides or fronts of boulders or logs are good primes.
Lakes: Both the edges and the midst of weedbeds (especially those that break the surface), structure (standing timber, etc.), and drop-offs are great prime lies. A less obvious prime can be in deep water, where fish may stratify when a food source like midges is present.