I am loving this new camera. Above water photos look great, too. A few people have asked, so: I bought a Olympus mirrorless camera (OM-D E-M5). It is much lighter and smaller than a DSLR, so perfect for traveling. It is a discontinued model, so there was is a fabulous sale including the underwater housing at bluewaterphotostore.com.
The GoPro filters I bought on Amazon but they are made by Backscatter. They have a macro adapter, too, that would be useful for taking close-up pictures… all the ones I try turn out blurry. (The GoPro is really wide-angle.)