This is a photorealistic under water scene, ready to render with Vray.
No additional work needed because all effects are done in the 3d scene itself, also the Lense Effect! If you download the Preview under the Previews section you can see a rendered animation without any post work.
You can edit every part on the scene like you want, so you can use that scene as the base for nearly every under water shot!
The little stones are scattered with Forest Pack. You will get a scene where you still can adjust the little stones with FP. If you dont have FP installed just use the second scene, there is FP collapsed.