The term "tuna" refers to a family of fish that covers 15 species. In the world of sushi, yellowfin and bluefin are the most popular tuna types, and they taste entirely different.

Yellowfin is mild in flavor and very lean, which it makes up for with a firm texture. Bluefin, on the other hand, is usually fattier than yellowfin with a much richer umami flavor.

Bluefin tuna is used almost exclusively in sashimi because of its bold, rich taste, whereas yellowfin tuna is versatile enough to be used in nigiri sushi and other dishes.