The TBH Morrish Sparkle Donkey Black from RIO is a black tungsten bead-head nymph tied in size #18. The tungsten bead-head helps it sink quickly into the feeding zone.
Euro nymphs are slim and heavily weighted to sink fast on a tight-line rig. Fish it as an anchor or dropper, staying in contact with the flies through the entire drift. Carry it in a couple of weights to adjust to changing depths through the day.
