Gefilte fish is an acquired taste. It is a traditional Jewish meal and a famous item of Israeli cuisine. It is sort of like fish meatloaf. It is frequently served with chopped horseradish or "bitter" greens, like parsley. It can be eaten anytime, but is often used as an appetizer in the Passover seder when horseradish and parsley are often part of the menu.
There are even vegetarian versions of gefilte "fish", see external links below.