Description taken from PC version of this game

First there were your everyday zoo animals, and then came the endangered species followed by African animals and dinosaurs. Now, you can expand your animal wonderland to include a variety of aquatic attractions in Zoo Tycoon 2: Marine Mania. Featuring 23 sea-faring animals such as the walrus, dolphins, humpback whales, orcas, stingrays, and sharks, the game lets you combine your existing land exhibits with nautical environments in free play or in one of ten scenarios.

Placing water tanks differs from creating a pen for land animals in that instead of worrying about horizontal space, you need to make sure that the tank is deep enough to satisfy the species who lives there. You can adjust how much your tank rises above the ground so guests can either look down into the water, see the animals from the side or a little bit of both. Terrain in the tanks will always be sand, however, Zoo Tycoon 2: Marine Mania comes with a variety of water friendly foliage including kelp, barnacles, sand dollars, and more to decorate each environment.

You may also please your customers by placing grandstands and show tanks that display orcas and dolphins that will perform tricks by jumping through hoops and playing with balls. Land amenities feature many themed stands and a swim shack for a quick dip during hot days. Maintenance workers can be given specific jobs in the expansion, and you gain the option to pick up guests and place them on the right path, or in a shark tank for a truly memorable show. ~ Gracie Leach, All Game Guide