I had a baby Siberian Sturgeon for a while, I bought it at my local pet shop after seeing a fellow post pics of his eatting out of his hand in his pond.
They are supposed to be hard to keep as a baby, but when they are adults they are very hardy. Mine didn't make it, and I just haven't thought about getting another. The albino's are supposed to stay small, under 1 meter I think. They also need tons of O2 more than Koi.
Here's a web site with info on them if you haven't found it yet :
http://www.sturgeon-web.co.uk/ I searched high and low but this place was the only place I could find with anything on them.