Answer: Sushi is generally not keto, but there are exceptions.
Most sushi is not keto because it contains rice, which is high in carbs. If you're dining at a restaurant willing to replace the rice for you, sushi can be keto-friendly. You can replace the rice with cucumber slices (known as "naruto style") or with cauliflower rice.
When eating sushi, be sure to avoid imitation crab meat, as it is extremely high in carbs.
Sashimi is a nice keto-friendly sushi alternative, as it contains no rice.