I pointed out a few of the ones that really stand out to me. If you look close, you can tell that what you are seeing is just the texture of the polyp fingers. So in that regard, it's a very good picture. However, to my eye, at first glance, it appears to be oversharpened, and that takes away from the wow factor. Wow factor is very important in contests. Depending on the amount of photography experience the other reefers in the contest have, they may see a picture that is too sharp, or they may see it for what it is - texture. It's a tough call, but #2 is also a very good photo, and with that one you take away the chance for someone to score your photo lower because it appears overly sharpened.
Did that make any sense? I participate in digital photography contests on a weekly basis, so I know what you're going though. When is the submission deadline? Take as many pics as you can before the deadline, then pick the best one. Never settle just because you got a good one - a better pic is always possible.