Animating an arrow

Hi I have modelled a pump and i would like to show where the oil flows by means of arrows.  I have made a 3d sketch for the path of the arrows and have modelled an arrow head with a path mate to the 3d sketch.  Can anyone think of a method for the arrow tail to follow the shape of the 3d sketch as the arrow head is animating

Abhinav

SolidworksAssemblies