origin: [9th Century] Japan; 煮凍り= boil + congeal
noun or verb
Basically, "fish gel" or making a savory gelatin from leftover parts of fish; aspic.
In the theme of responsible eating, sometimes termed "Nose to Tail" (a phrase coined in the book The Whole Beast by Fergus Henderson), nikogori is an ancient traditional method of Japanese cooking/food that involves boiling the fish bones, scales, head, and tail to extract a nutritious & tasty jelly. You can add other types of gelatin, such as agar agar, to the mix.
The nikogori jelly can then be used to encase or accent other foods. And much like "beef tea" or bone broth, it is not only very nutritious and socially responsible, but also useful for invalids or anyone with chewing issues; jelly is soft and melts easily in the mouth, simplifying consumption. Others may simply enjoy the texture of jell-o or the crystalline appearance it allows in food presentations.
Unagi Nikogori (or eel encased in fish gelatin); see more of this amazing meal here.