There's not a lot to do in Las Vegas with kids so when you find family friendly entertainment you're willing to splurge a bit. $95 for family of four and we enjoyed the aquarium for about an hour.
There are various underwater fish to view and I love the tunnels you walk through to view aquarium. We spent some time sitting and watching the sharks and turtles.
Kids loved it and were mesmerized by the sharks.
I hear you can get discount tickets- do some research. 4/5 only due to price.