C-750 - lens adaptor and wide angle vs fisheye

I am looking at getting the CLA-4 55mm lens adpaptor for my C-750. Can someone tell

me if this allows any 55m lens to be attached (providing they have the same attachment

method) or can only olympus lenses fit?

Also, I would like to get a fish eye lens that can give me 180 degree scope, but the

olympus website only lists a .7x wide angle. Can I get just any 55mm fisheye lens? Are

there any pros or cons to consider?

Thanks in advance for your help.