A mid-to-late summer hatch in the U.S. West, nocturnal stones hatch at night but trout are still looking for them come morning time! Will Dornan's Water Walker is one of the top-selling stonefly patterns at our shop for good reason -- It floats like a cork and has one of the most realistic profiles of any stonefly dry out there. The nocturnal stone variation is one of our go-to nocturnal stonefly imitations.