I was on the Carnival Glory last year and had some Sushi there. I don't know if the Fascination's sushi bar is the same as the Glory's, but since they are the same cruiseline, I would imagine they would be quite similar.
People said that the sushi was really good. I am not an expert at sushi. The only sushi I can recognize is the California Roll, which they had. I did see other rolls, if a roll is round shaped surrounded by rice. I saw rolls that had sesamee seeds around the outside of the rice as well as small fish eggs (caviar?). I did see sushi in the shape of cones, with sea-weed being the outermost layer of the cone. I did see sushi where the fish is on top. I saw sushi that contained fish and cream cheese. I saw sushi that had smoked fish (eel?). They had the typical sushi condoments: chop sticks, Soy Sauce, sliced ( & pickled?) ginger root, and lets not forget Wasabee. I have had Wasabee sauce before, and the one in the Glory's sushi bar was really potent; it felt like my sinuses were on fire; it almost made me cry. The best thing was (like most of the food) it was free and all you can eat! I hope this was some help to you. Have a good time on your cruise and Bon Appetit at the Sushi Bar.