Yes, we succumbed and paid $15 each to see the Secret Garden (as cheesy as it sounds). But it was worth it.
Here you got to see dolphins in the dolphin pool way up close (unlike at other aquariums) and see a baby dolphin with its parents in the dolphin nurturing pool. Then in the tiger area you got to see the usual adult tigers but right now you can also see 4-5 tiger cubs and watch them all interacting playfully with each other.
Bottom line: Nice break to the typical Vegas madness and sounds of slot machines. Great place to bring someone who likes to see animals, esp baby tigers and dolphins.