I am a sushi junkie! I love sushi. Maybe I can give you the answer you are searching for. The white fish you had at the first sushi bar is called escolar, they refer to it as "white tuna" but it is not of the tuna family. You can learn about it on Google. I am a yellowtail eater, and when I first tried the escolar or white tuna, I was blown away. It has become my favorite sushi bar item. I hope that helps you. Aloha from the island of Kauai.