On the planet of Risayn the locals are almost exclusively pescatarian. Since First Contact, Earth-style sushi has become an incredibly popular dish in cities and smaller settlements alike, though they often use other ingredients instead of rice, which isn't well known to the inhabitants. It is seen as an important cultural link between Earth and Risayn and is often served when humans and the locals meet.
Interesting. What kind of food did they have before humans introduced sushi? Or was sushi just a novel combination of foods that they were already eating at the time?
The planet is mostly water and the denizens are amphibious so they mainly eat fish. They do have some very primitive agriculture but on the whole they consume fish far more than anything else