I did a class at an elite sushi restaurant in Denver (gift for GF). They would order for you and sell you the fish. I would go to an elite sushi restaurant and ask.
As that sushi restaurant is too far away for us to use for good fish, I like to get supermarket salmon, marinade in teriyaki, and grill. Serve it on some rice with wasabi and siracha mayo. Not sushi, but a good substitute.