Diawl Bach fly, Welsh for ‘little devil’. This all round nymph attractor pattern can be fished in a variety of ways and it gives excellent results in rough water, as well as, calm. The Diawl bach Nymph Trout Flies are suggestive of all sorts of aquatic insect life, especially midges. In Britain and areas of Northern Europe the Diawl Bach Nymphs have become one of the most popular still water flies of recent times. The secret to the Diawl Bach Trout Fly, is its sparse, nymph like profile which makes it a great choice for all seasons and conditions. Carp and trout adore the Diawl Bach Flies.