In the past, I used a bookshelf to place my fish up high with no easy access for the kitty. I had three bettas that were all happy up there and kitty stared but didn't dare. I'm hoping to install some floating shelves to put my fish and knick knacks on.

I do like the idea of a Japanese theme...I know you're trying to be silly but instead of doing something obvious, use the subtle zen aspect and feng shui and maybe do a bit of a geisha dressing room.