Went to Shark Reef at Mandalay Bay while in Vegas because I really wanted to see an aquarium. It was a bit overpriced and small, but I enjoyed it nonetheless and I stopped to look at everything. Everything. There are plenty of things to see. My favorite had to be the last thing you see, you walk into a tunnel and there are sharks swimming all around you. Pretty awesome, I think I sat in there for about 30 minutes or so, just watching them all.
Oh and I loved the touch pool..who got to pet a stingray?! This girl. :)