Description
Mayfly Nymphs – Life Below the Surface
Mayfly nymphs are the engine of the river and lake ecosystem. They are active year-round and represent a constant, reliable food source for trout and grayling from early spring to late autumn. To fish a mayfly nymph successfully, you must understand their behavior. They are categorized into three main types: Digging, Swimming, and Clinging nymphs, each adapted to specific environments.
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Digging Nymphs: Found in lakes and slow-moving river sections with soft or sandy bottoms. These include some of the giants, like the Green Drake (Ephemera danica).
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Swimming Nymphs: Agile and active, these are found in both still and moving water. They are often drift-feeders, like the Claret Dun (Leptophlebia).
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Clinging Nymphs: The "bodybuilders" of the mayfly world. Short, compact, and powerful, they live on rocks in the roughest currents, like the Yellow May Dun (Heptagenia).
Our Commitment: Anatomical Accuracy & Performance Since mayfly nymphs spend most of their lives tucked away near the bottom, they only become truly vulnerable when they lose their grip, drift to find food, or begin their journey to the surface to hatch. This is when the fish strike.
Our commitment is to provide imitations that match the specific silhouette and behavior of these three categories. By using J:son’s unique materials, we create nymphs with the correct proportions, lifelike legs, and balanced weight.
The Ethical High-Contrast Sinker – J:son Tungsten Mayfly Nymph 4 Black BL (Hook #14) The Barbless Tungsten Black Nymph 4 in size #14 combines extreme realism with ethical angling. Tied on a high-quality barbless hook, this fly is designed for the modern angler who prioritizes easy unhooking and minimal impact on the fish, without sacrificing performance. The black coloration provides the sharpest silhouette underwater, making it a high-visibility target in both crystal-clear streams and darker, peat-stained waters.
This nymph features integrated tungsten weighting, giving this small #14 profile the mass required to sink quickly and stay in the strike zone longer. It perfectly mimics the darker swimming nymphs often found in faster currents. J:son’s signature anatomical design—including a segmented body and lifelike legs—ensures the fly looks alive even when dead-drifting. This is an essential pattern for technical "Euro-nymphing" or traditional indicator rigs in catch-and-release waters where a deep-sinking, realistic, and fish-friendly fly is required.