Many many fish species, and turtles and birds and echinoderms and corals and jellies, etc. Hooray for Pixar's "Finding Nemo" :-P
Penguins swimming and diving and grooming and jiggling their tails (what was up with one, I wonder?) and chilling near the air vent. Very familiar =)
Big puffer fish!
I like the jellies that produce the iridescent effect with tiny reflective cilia. There seems to be a bioluminescent source in the middle, and the cilia refract the light in a most mesmerizing pattern... and the ones with spots marking Voronoi regions :-P Both species are Australian, I think.