Best Wide Angle Approach for Olympus E-PM1 with PT-EP06L

I am confusing myself in what my options are for wide angle for the above combination of camera and housing. I've seen fish eye lens for the camera and wet lens for the housing. Not clear if they are used in conjunction of independently.

I presently have the stock 14-42mm lens.

Thanks for any insights or advice.

I have the same camera but the PT-EP06 (no L lights). I found a micro 4/3 Olympus 9-18mm on eBay for about $500-$600. Great lens! I also replaced the port with a domed port from Zen Underwater. It's the wa100ep. Here's the link on Reef Photo: http://reefphoto.com/shop/index.php?main_page=product_info&cPath=80_126&products_id=4798

Thanks Kent. That explains the relation between the wide angle lens and need for a dome rather than the standard flat port.