I've always wondered if you had a pair of, say, acrylic tanks that were linked with a pair of tubes... 6 or so inches wide, and the current was encouraged in such a way as to make them one way paths to and from the tanks, how schooling fish would react... I just picture a school of chromis riding the current in a circular motion -- ride one tube, then ride the other, over and over... that would be endlessly amusing

-Corruption