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 Giant Deep-Sinker – J:son Tungsten Mayfly Nymph 4 Light Olive (Hook #4) The Tungsten Light Olive Nymph 4 on a size #4 hook is a formidable imitation of the largest mayfly nymphs in our waters. This "heavyweight" version is designed for those specific moments when you need a massive profile and maximum sink rate to reach trophy fish in the deepest, fastest sections of the river. The integrated tungsten weight is concentrated to pull this large fly down quickly, cutting through the most turbulent currents to find the big trout holding in the shadows.
This light olive version provides a natural, translucent look that is particularly effective for mimicking the large, pale-toned digging nymphs found in many river systems. Despite the substantial size #4 hook, the fly maintains J:son’s legendary anatomical realism—featuring a large, segmented body and robust, lifelike legs that provide a massive presence in the water. This is the ultimate "anchor fly" for heavy nymph rigs or a standalone choice when you are hunting the biggest fish in deep pools and fast runs where only a fly of this magnitude will get the job done.