There must be a fish with head and tail on the New Year's Eve dinner, and it must not be finished.
The most important thing for the New Year’s Eve dinner must be a complete fish, preferably with head and tail. The word "fish" has the same pronunciation as "surplus", so having fish every year means "having more than enough every year". It is best not to finish such a fish, as this means that there will be "surplus" in the coming year, that is, "surplus every year."
The placement of fish is also particular. Generally speaking, the fish head should face the elders, which means respecting the elders. The fish belly should face the literati, which means there is ink in the belly.