The Grannom pupa (nymph) has a light green segmented body with thin black bars and a silver bead. The adult fly is roughly the same size as the pupa with broad wings and a darker purple/brown body.
The Grannom is a small sedge, which usually hatches for 2 weeks during the month of April. Historically it is seen as the start of the Dry Fly season, as the Grannom is generally the first fly the trout "look up" for!
Grannom hatches only usually last for a few hours each day, generally occurring in the morning between 10am and noon. The duration of the Grannom hatch is usually for 2 weeks in April, generally starting anytime in the first 2 weeks of April (in the south of the UK) to the last 2 weeks of April in the North and Scotland.
These nymphs are available in either size 14 or 16.