Here is Wisco's guide for the tortoise:
Meiolan (Giant Tortoise)
Exhibit size : 10 x 10 ( 100 squares )
Fence Type : 40x low rock wall ( exhibit must be sunk 2 tiles! )
Terrain : 60 squares fresh water, 30 squares snow and 10 squares gray stone
Foliage : 3 squares full with artic grass
Rocks : 3 medium aquatic rocks
Shelter : no shelter
Toy : no toy
Elevation : no elevation
Animals : 1 male and 1 female
Animal Happiness : between 96-100
Suitability Rating : 101
Total Cost : $ 17.450
Cost/Square : $ 174,50