On monitors you can scroll over the signs. That way the signs are also very easy to put in, when a new species arrives. Just an upload to the computer.
The day we visited Hamburg it was quite crowded and we were in some kind of time limit so I didn't notice all the signs, and because I'm not a fish-expert I asked.
I was only one time at that place many years ago-it was so crowded that day and everything is very small, so I left it after a couple of minutes-so I can't remember of any tank signs...
