Question: are fish bladders used to filter wine?
Answer: Isinglass (/ˈaɪzɪŋɡlæs, -ɡlɑːs/) is a substance obtained from the dried swim bladders of fish. It is a form of collagen used mainly for the clarification or fining of some beer and wine. ... The bladders, once removed from the fish, processed, and dried, are formed into various shapes for use.