I frequently find myself craving sushi on a Sunday evening. But I have been told by a local sushi chef that the fish is not as fresh on Sunday or Monday since the fish markets are closed those days and/or no one is bringing fish in from boats those days. My experience has been consistent with this. Obviuosly this would only apply to the better sushi places that don't store their fish for a few days anyway. I'd be happy if someone could debunk this theory so that I can start looking for good fish on a Sunday or Monday night.