In electroplating apparatus, a paddle or agitator agitates electrolyte in a vessel to provide high velocity fluid flow at the surface of a wafer. The agitator is designed and/or moved to also selectively shield part of the wafer, for example the edge of the wafer, from the electric field in the vessel. Selectively shielding may be achieved by temporally shifting the average position of the agitator towards one side of the wafer, by omitting or shortening slots in the agitator, and/or by synchronizing movement of the agitator with rotation of the wafer.