It's not really interesting. The far sea is default shader+ translucency, foreground glass shader and some of the default shader's color as density. With the default shader alone, I couldn't get the water transparent like it seemed in the waves, which is probably logical. In the waves, the fish were probably just the shadows projected on the side of the curl.
Anyway, when you have a normal seafloor, you get strange bands in the water, here I disabled render surface in the planet.
I quit.
