Gefilte fish is indeed authentically Jewish, to prevent people from taking bones out of fish on Shabbos. Everything was ground up together and made into balls and boiled. And nowadays I also like to take thawed gefilte fish loaves, mix in an egg, some sugar, grated carrots, and onions, and bake them in colorful layers, alternating whitefish and salmon (to which I add some chrein to make it more obviously pink). Sometimes I will add frozen spinach to the white gefilte fish, to speckle it. I put it in a small wide loaf pan and bake it for about an hour at 350 until the top is golden-browned.
When in the mood, I marbleize the two fish mixtures together, by putting large alternating scoops of fish in the pan and then running a knife through them. It looks SO pretty and tastes delicious. To serve in a really pretty and functional way,cut the ends off an unpeeled cucumber and then cut across the width into thirds (or fourths,depending how long the cuke is) and hollow out a nice hole in each section, not cutting all the way to the bottom. Fill the hole with chrein, chreyonnaise, or mayo, and serve on the side of each plate.