QUESTION:  
In my aquarium, I have a pump that makes bubbles in the tank. 
Does the tank that you have your fish in have a pump?  How big of bubbles
does it make?  How do they know which way is up? 

ANSWER from Marilyn Vasques on April 27, 1998:
Our tank does have a pump that circulates water but we don't bubble
air into the water like you do in your aquarium.  Air flows through a
special filter that allows only oxygen into the water so there are no
bubbles.