Look at any fast river and you'll see pockets where the water looks still — a calm circle behind a boulder, a slack patch on the inside of a bend, a soft spot between two rocks where the current splits. These are eddies and soft spots. They're where fish save energy.
A trout fighting full current burns calories every second. The same trout sitting in an eddy spends almost nothing — and is positioned to dart out into the seam to grab food, then retreat. Eddies turn current into a feeding station.
Where to look:
- Inside of any bend in the river. Current accelerates around the outside; water on the inside is slack.
- Behind any rock sticking up out of the water. Even basketball-sized rocks create soft spots big enough for a 16-inch trout.
- Below a downed tree or root wad. Slack water plus overhead cover — premium real estate.
- Where a tributary enters. The slower side of the merge is often a long eddy.
Fishing them: cast across the seam where the eddy meets the main current, not into the eddy itself. The fly drifts on the fast side, the leader sits on the slow side, and the fish — sitting in the eddy — sees the food drift past in its cone of vision. A drift through the seam is the most consistent shot in moving-water fishing.