Hmm,....
so when i take a look at this picture: http://www.zoochat.com/36/chinese-giant-salamander-323142/,
the head of the animal is in the right corner of this enclosure?
then it's an impressive specimen, assuming the tank being a least 2m in length,...
But it's also a quite small exhibit,....
Your rigth, it is a very large specimen and your right also that the enclosure is relative small. However, if I´m informed right, Rotterdam has a second enclosure ( behind the scenes ) which should be much larger and mend for breeding. It is even possible that the behind the scene-enclosure and the display-enclosure are conected with each other but as said, not 100 % sure.
Oh, i assume this one is also no longer visible, as all other terraria in the Riviera Hall are. Do you mean the passage to the Toucan and Marmoset enclosures on the right side of the Riviera Hall, right of the passage to the chinese garden? Any pictures of the behind the scenes tank?