A really nice aquarium. The biggest part of it is enjoyed from one of those moving sidewalks while the fish swim around you. My kids love those types of aquariums because it puts you in the underwater world with the sealife and makes you feel a part of it. They had a large assortment of fish to enjoy too! There was also a touch pool to enjoy and several other cool experiences to bring kids closer to the underwater world. Located in the Mandalay Bay Resort and casino, you will have to seek this place out. It's located back behind the area where all of the casino's restaurants are.
Check it out:
http://www.mandalaybay.com/entertainment/sharkreef.aspx