How would a voxel know where to move? I mean you could fade teh two but teht would for most sims be not very impressive so you will need to have something mroe than just 2 fluid containers you wish to morph. Somnething must tell the computer how.
You could use particles as seeds for the fluid morph tough. So if you can sedicribe teh particle system you could move thet date over to the voxel system. But that is if you knew how to do this with particles you wouldn't need the fluid.