Shnimpon.... The size really depends on how big it is at the moment... Small hatchlings can go into a Plastic Tub.. Yearlings into somthing around the 3-4 ft wide x 1-2 foot high. And then for adults you would be looking around the 4ft wide x 3-4 ft high x 2ft deep (At Least). They can grow up to approx. 3 metres....
Get some books... and read up....
Where are you based...I might be able to lend you some of of mine....