How long does it take for sushi to spoil unrefrigerated?

Sushi (the seasoned rice mixture) itself can last for a few days before it's overall quality is diminished.

However, sushi in the sense of raw fish with said rice and other ingredients is supposed to be made with fresh fish and should be consumed in a day or so of its making and this only if it has been kept in optimal conditions (not left to sit out at room temperature and kept in a cool place such as a refrigerator)