Hey, that’s what came to my mind when I read the question.
But you need to take that a little further, though.
Take the animated fractal noise layer and precomp it, then use it as layer map
in caustics and select it as the water. This should give you some beautiful
looking water. If you need to, go back and adjust the fractal to change your
water to suit your needs.
Also in caustics, get a photo of ocean floor and use that as the bottom and so on.
Good luck.