the PS work doesn't need to be so drastic, IMO. The photo is pretty darn good to begin with, not a lot of work needs to be done. Here's my take on it.
For what its worth I do photo editing jobs from time to time for various sources... Not a pro by any means, but I'm not a novice either. I just brought out the whites, made your coralline stand out a bit more and kept the dark background. Like I said, your photo is pretty good to begin with.