For many, January still water fly fishing will be small still waters. These tend to fish really well during the winter months. In terms of hatches, midges will come into their own during the Winter as a stable food source for cruising fish. During milder periods of the day, sporadic hatches of midges may bring fish up to the surface to feed or the fish may feed on the bloodworm larvae closer to the bottom.
If the fish are up feeding on midges then a small black buzzer or Diawl Bach just under the surface can work wonders. If nothing is rising, try a bloodworm fished very deep and slow. Alternatively, large lure or boobies fish slowly on a sinking line can tempt rainbows to take the fly.