The tuna is too dark
"Once you cut the tuna and it's exposed to oxygen, it becomes very bright. But after that brightness goes away, it starts getting really dark and oxidized. That's an example of a fish that you can see as a red flag."
It uses leftover fish
“When you see two or three different white fish mixed with pickled vegetables, that's all about using the leftovers.”
It has only one variety of each fish
“At my restaurant, we normally have three or four choices of sea urchin. I'm hoping that you're gonna have two or three types of tuna, salmon, whitefish, shellfish, scallops, shrimp. What's fun for me is to try them side by side to see which I like best, and challenge myself to understand the different nuances. It's almost like tasting wine. If you're not able to try to taste these nuances, that's a red flag.”