One of my favorite forms of fly fishing for wild trout in mountain streams is seeing trout on their feeding stations then going one on one with each trout.
As I sneak in below a pool in a mountain stream I seldom spot the trout holding his feeding station. Rather I see some physical feature which draws my attention to a specific location. Then by closely examining that area, I actually identify the trout.
The easiest physical feature to spot is his movement which I discern as he relocates on his feed station or as he turns slightly to take a natural nymph. Thus revealed, I can drift a fly to him and catch him.
An unusual shape in a pool which appears out of place in a pool often reveals the trout. This may be a long slim body lying over a small pebble stream bottom, or the straight edge of a brook trout’s tail as he lies beside round cobblestones on the stream bottom.
The dark back color of a mature male brook trout holding over a light sandy stream bottom is a quick give away as are the brilliant ivory edges of the brook trout’s fins holding beside dark stones.
The shadow of a trout on the stream bottom on sunny days is often easier to spot than the trout as long as I’m careful not to throw my shadow over the trout. Study this carefully because in deep water the trout’s shadow may be focused several feet from his actual location. This is exciting fishing.
I cover a lot of this in my book Trout Fishing in the Shenandoah National Park.