Good start. Nice corals.
For some reason, maybe simply a lack of sufficient coffee, I'm not seeing an ISO value listed with your EXIF info.
All the shots have a super low aperature / high fstop value (like f32-40). You can get better detail resolution with a more midrange fstop like in the f11 range.
You can probably go with longer shutterspeeds if you want as your subjects are fairly stationary.
How are you white balancing the shots? They look fairly blue to me.
Compositionally, the subject in all your shots is fairly centered which makes for a decent depiction of the subject but results in less interesting photographs.
Putting a carriage return or two between your IMG tag pairs would help to separate the images a bit in your post.