Has anyone ever wondered why cruise ships don't have really neat centerpiece aquariums like in the restaurants, etc? It would be perfect to have a little piece of marine life on the ship since you're sailing on the ocean! Of course I don't mean gigantic animals like sharks or rays, but little fish and crabs - creatures like that.

 

I assume it is probably a logistic problem with being on a moving vessel or cleanliness or something.

 

Thoughts?