Officers responded to the Long John Silvers on North First Avenue shortly after 11:00 Saturday night.
An employee says he was taking out the trash when a man demanded money and started to stab him with a knife.
Police say he managed to use a trash can as a shield.
Employees inside the store say a woman came into the restaurant, grabbed the deposit bag and cash from the registers, then took off.
So far no arrests have been made.