There's no Rialto fish market on Sunday or Monday, so those are the days you wouldn't normally order fish. However, lately the fish has been arriving from further away on these "off" days, so if you know you're eating in a reliable restaurant, I still think you can count on the fish will be fresh.
The question these days is, is it farm-raised, or from the sea...
Thanks for the information. I'm meeting a friend for dinner one night and she's not much into seafood, so I'd rather pick a night and place that would satisfy her, as well as me. Will do Monday.