Yeah, I agree with statements. Too saturated in some areas altho the water looks a bit grayed, as well as clear, but I think some of those suggestions would fix that. If you are using caustics I have found in situations it can oversaturate, but you can always post-process.I was using irradiance mapping and think it may have a bug there. Will have to look at it further. Your fish looks happy!

No need to think outside the box....
    Just make it invisible.