needs more contrast and saturation. do you have a polarizing plug-in? it could be spectacular. as it is.....it's still good. let me tell you what i did to your pic. first i selected the pale part in the middle. then i went to select inverse. i gave the outside coral more saturation and then went to work in levels giving it more depth of contrast. then i did the middle part doing the same thing. i think the two parts need to be treated separately. try it and tell me what you think. this same idea could be tried with all your underwater shots. they'll look clearer. (i think)