Like most of us I use many types of indicators for various reasons. One of my favorites is the corkie style. It’s made from closed cell foam and has a hole that goes through the center. I like them because they are easily adjusted and hold tight. Many anglers use a toothpick to lodge through the hole to secure the float against the leader. I prefer rubber tubing or rubber bands so I can remove them easily. This is also resolved by purchasing them with a precut slit or cutting your own. The primary function of an indicator is to indicate a strike but another, as important, function is to indicate what the fly is doing below. A foam type of indicator serves as a float because it suspends the fly. Exactly it’s a bobber.
When hanging nymphs beneath a float, drag-free drift is the primary objective The angle of your toothpick or other material also serves as an indicator. It indicates how properly the fly is drifting. Let’s define the toothpick or other material as the post. Allow me to preface that there is more than one indicator nymphing tactic and that the following is a generalization on the topic.
If you are attempting to bounce a nymph along the bottom, then your post will angle downstream. That may come to a surprise to many but it’s true. The reason is because the water near the surface is moving faster than below near the bottom.
If the water is slow moving then the top and bottom flows will not vary in speed as much thus you will see more of a straight up angle of the post. If the post is angled straight up and it does not angle strongly downstream once in awhile, or the does not twitch, then there is a good chance that is not catching the high spots of the bottom and could very well be out of the zone. By the way if you see the indicator twitch set the hook always; don’t get lazy.
When mending your fly line watch the angle of the post from angled upstream to straight up, followed by downstream. You will refine your nymphing expertise by monitoring the post angle.
There are many sources to learn more on the subject but one that may be overlooked by fly fisherman is learning through centerpin tactics.
Buy your fly fishing indicators here.