If I may, to critique the photos to help you and other folks take greater shots of these beautiful creatures:
image 1) has a staggeringly too shallow depth of field. Reduce the aperature (make a bigger F-stop number) and increase the light above the coral and then the specimen will be in sharper focus over at least the depth of its body
image 2) same as above, except this one has an additional problem: you exceeded the minimum focal distance of your lens. When you get closer than the min. allows (check the mfg website or your manual to see whatthat number is) what happens is odd things like we have here: the foreground is out of focus because you got too close, the mid ground is clear(er) and the background is out of focus (shallow depth of field)
FWIW, my friend
With a little adjustment, you could take even better photos.
if handy, do check out my first issue of the C Journal... it has a photography column with an article that is a crash course on aquarium photography. FWIW