Originally posted by BigDoggProblem
The whole point is to deduce that the German owns a fish, and not to engage in overly semantic psychobabble, or play "Simon says" with the wording.
I completely disagree with your interpretation of Einstein's intent.
EDIT: Interpreting the riddle your way makes it as worthless as FrenchQueen's "which word in the English language is most often pronounced incorrectly?".
You're about as thick as it gets. 'Semantic psychobabble' You're career (if you are old enough to be out of nappies), must be in something that requires no brain, like siliva production.
FIrst, after some research, you will find that Einstein cannot be definatively credited with the origin of this riddle. You will also find that about 98% of people try to get an answer like yourself and ignore the actual question and instead make a convinent other question. (Someone owns a fish, so who seemingly owns no pet?) This is where the author of the riddle traps everyone. This is not intended to be a huge problem solving venture, but rather an exercise into how the solver comes to grips with the problem.
Show where in the puzzle it DEFINITIVELY can be concluded that ANYBODY owns a fish. And do it without making an assumption that may or may not be valid. YOU CANNOT DO IT! (I'll save you the trouble, so that you can continue making drool.)
So although you believe that you have to deduce something from the questions, remember the source is a scientist or mathematician (as the author may not actually have been Einstein, but instead Lewis Carroll). These are not individuals who revel in assuming things and leaving questions not completely answered. So go troll elsewhere, you're input is irrelevant.