Here you have some pictures of the Oceanarium of Lisbon, visited in May 2012.
It was pretty hard to take the pictures cause I just had my broken 85mm lens, which just works in Manual focus.
So imagine to try to capture the animals moving all the time, and with low light conditions.
Anyway I'm kinda happy with the result.
Here the pics of another Aquarium I visited 2 years ago: Shedd Aquarium in Chicago:
In that occasion pictures where taken with my 35mm. Better choice for the occasion, definitely.