Nymph Flies: In simplistic terms, a nymph fly is a type of fly fishing fly that imitates the naturally occurring insect larva and nymphal stages of aquatic insects commonly found in streams, rivers, ponds, and lakes. Nymphs are commonly found under or on rocks, in aquatic vegetation, fallen tree branches in the water, and even in gravel, sand, or loose sediment. They do not have wings nor can they fly in this insect stage. Instead, they scavenge and hunt for food by crawling along the streambed, which means they constantly live underwater. Because of this all nymph patterns found in fly fishing are used to sink and to be fished under the water. These do not float.Can be weighted by beads or wire wrappings or unweighted.