Unfortunately, theres probably not much you can do.... Most 'public' tanks like the ones in some restaurants are there for the 'wow' factor, Mommy, can we go eat at the place that has the cool fish? Yes darling, you get the idea. They probably pay a minimun for tank upkeep and have no problem simply replacing the fish with another from a wholesaler when it dies. Dont get me wrong, Ive been in eateries and even hotels that sported beutifly kept aquariums. Just not the norm, I say, make every attempt you can to try to educate.. Good luck and let us know how it goes...