Wetfly Scud Olive Nymph Trout Flies, 1 Dozen Fly Fishing Flies Wetfly Scud Olive Fly, 1 Dozen Fly Fishing Flies Scuds are must have in any fly box Scuds are a common and high protein food source in many stillwater lakes and trout tailwaters Scuds actually live and breed in nutrient rich lakes and then flush out of the bottom of many tailwaters Scuds are full of protein and are responsible for allowing trout to grow to enormous sizes