I've been invited to a sushi-rolling party.
I've offered to pick up something from Citarella or Zabar's on the UWS. I don't know what they have for sushi, but I've heard that there's "sashimi quality" fish out there, a higher retail grade than what's normally sold for cooking.
Am I being too persnickety? If not, what should I be looking for? Always saltwater fish, not freshwater, right?