Will fill out some detail and post the links to the products used here.

And here are the first results after a couple of tanks in Carlisle Bay I quickly edited the best of the footage together including some slightly pixelated zoom shots.
The GoPro can handle a bit of that but it isnt going to be a MACRO shooter at all.
I also notice that its very inconsistent, this could be due to my use and non use of the light.