The upstream presentation places the leader directly over the fish’s back and the fly lands directly in front of the fish. Try to cast precisely between the fish’s eyes. Fish see poorly directly above their backs and a fly gently delivered on a flexible tippet may go unnoticed. This presentation can be a deadly method demanding extreme casting accuracy and delivery. Using an open looped delivery cast helps slow down the fly and line speed which prevents water splashes from the line. However, this method is limited to shorter casts.
The distance to lead a fish depends upon the depth that the fish is holding. Since a fish’s vision window expands the deeper it holds, a deep holding fish must be led farther than a shallower holding fish. This allows the fly to land just outside of its vision window. Use caution to make sure that the line and leader junction lands well in back of the fish.
Also a deeper holding fish takes longer to rise than a shallower holding fish. Simply, the deeper fish has a greater distance to travel than a shallow fish.