Stoneflies are found all over the world. No matter where you are, they have some things in common. They need clean freshwater to survive and they are only found in moving water. They also work well as attractor flies when fishing new waters in search of good fishing spots. Often called the “year-a-round-fly”, stonefly nymphs are active all year around and are therefore important. They are rarely of huge importance during a hatch as most species just crawl along the bottom on to rocks at the shoreline to hatch. But, fish will feed on them all year and especially large sized nymphs will seldom be ignored by a hungry trout. We recommend that you use a J:son Swivel for all your fly fishing, no matter what type of fly you are using. However, it is necessary to use a J:son Swivel whenever you fish a size 1 or 2 J:son fly.