Get Mermaids
Place the mermaid statue in a tank with water in it. 
The statue will begin to shake and will become a mermaid.

Hector Dolphins
Name a Bottle Nose Dolphin "Hector" and you will have a Hector Dolphin.

Seahorse
Name a guest "Horse" and go to the adopt an animal screen and the 
seahorse will be there.

The Angel Fish
Name two of your guests Fins and you will get the Angel Fish.

Unlimited Money
Press $ and shift and hold them and watch your money go up rapidly! But to make 
sure there is no pain in getting millions of money make sure you do it at the 
beginning of the game when you have no enclosures otherwise the tanks will get 
dirty.

Change pointer hand color
Press [Ctrl] + C.

Photo Booth
Unlock the Shark World level and the Photo Booth will also be unlocked in the 
structures menu. 

Moving decorations
If you put the clam or treasure chest in a tank filled with water, both will open and 
close.

Unicorn Exhibit
Rename an exhibit to Xanadu to see the unicorn exhibit.


 
Hexcheat:
Go to folder install Zoo Tycoon
Click right mouse in zoo.ini ( Configuration Settings )
Select Properties, click out Read Only then click OK
Next, you open this file - zoo.ini - and then find line have this text:
MSStartingCash = 8888888
MSCashIncrement = 100000
MSMinCash = 8888888
MSMaxCash = 9999999
 
and then you change value of money.
 
 
10,000 Free Money: 
While the game is unpaused, hit shift+4 ($) for 10,000. 
Warning: Using this cheat will cause your marine tank water to 
become dirty!
 
Hint:
text: IF YOU PUT THE "MERMAID STATUE" INTO THE TANK, IT WILL TURN 
INTO A "REAL MERMAID". IT SO REALLY AMAZING!BUT IT JUST ONLY THE 
FEMALE MERMAID!
 
Hint:
If you name an exsisting exhibit "xanadoo" then you get a "yeti" 
(some kind of big foot/abombinable snowman thing).  
Make sure there's two 'O's on the end instead of a 'U'. 
 
Zoo Tycoon: Marine Mania Demo Game:
Press Up, Left, Down, Left, Right, Left at the title screen; 
a sound will confirm code entry.