If you are ever in Australia, the Sydney Aquarium is worth a visit.
http://sydneyaquarium.myfun.com.au/Exhibits-and-Animals/The-Experience.htm
The big walk-through pools, one with Dugons and smaller fish, the other with big sharks and rays. The reef tank that you actually walk though. Glass floor, roof and walls. It puts you in the tank, and the fish swim around you. And dozens of smaller exhibits with all sort of interesting critters.
Well worth a visit if you are in that part of the world.
I'm from NZ, so it's 3-4 hours flying to get there
Ian