A fly for mid- and late summer fishing when caddisflies are most abundant. There are many species of caddis flies that have the behaviour of swimming to the shore before hatching and this is the fly for this kind of fishing. Pupas that are ready to hatch ascend towards the surface and swim into dry land to transform into the adult insect. This fly is foremost a fly for river fishing but there are also caddis flies found in lakes and stillwater with this behaviour. The pupas are active in late evening and night. In Scandinavia there is still bright nights in july and august and that is the best time for this kind of fishing.
F-Ismo or Foam Ismo is based on the idea from the popular Ismopupa, a fly that floats well on the materials used, that can skate on the surface to mimic the swimming caddis pupa. This fly lays heavily in the surface like flies made of balsa wood, and provides a very good profile. The legs and shape of the fly is the same as the original Ismo, to create the correct profile and movement like the real pupa when you let the fly drag down and across the current. The real pupas swim down and across, this is what you should strive to imitate when you fish the fly. Before fishing apply regular dry fly gel to the entire fly.