I have gone to Vegas many times and have been to Yellowtail on a few of those trips. It is a very pretty restaurant located in the Bellagio Shops not far from the Casino entrance. There is a long bar in front and the dining in the back which also includes out door dining that overlooks the Bellagio Fountains and the show they put on. The environment is chic, comfortable and the staff is very good.
The bar is very petty and they make a great drink something many sushi places don't do well. Here the drinks are strong, it could be because it's Vegas. The staff is knowledgeable.
The food is fantastic. Plates tend to be small but that works well as it lets you order many different things. Some stand outs from the shared plates for me are the Lobster Carpaccio and the Yellowtail Serrano amazingly light and citrusy but both with some spice to them. Both of these are cold plates and i could not get enough. We reordered these multiple times. The warm shared plates i enjoyed were the Black Code and Seafood Dynamite. Both were wonderfully balanced with many layers of flavor.
We ordered quite a bit of sushi and i am not sure now what all of it was. I had my standard Dragon Roll, Tempura Shrimp and then some of their specialty rolls. Fish was very fresh and the rolls were made well. All of it was good. I am not a dessert eater but the Chocolate in a Cup was excellent. Their Lava Cake is also good.