Press [Shift] + 4 to get more money.
Note: Using this cheat will cause your marine tank water to become dirty!
To unlock the hidden mermaid, place the mermaid statue in one of your marine tanks.
This code from Zoo Tycoon still works with the expansion pack. Just rename one of your exhibits Xanadu and you will unlock a unicorn in the animal panel. You must rename the exhibit. If you try to name a new exhibit Xanadu, your game will probably crash.
Unlock the Photo Booth
After winning the Shark World scenario, you'll unlock the photo booth. Check your structures menu and it will be there.
Scare the Children
To make children guest upset, name a male guest "boogyman" and they will run screaming.
(supplied by: Daddysgurl1389)