It's used and is a delicacy
Had a acquaintance years ago who was asked by his landlady, if he ever caught carp on his fishing trips.
He gave me an aside, and said that he was dumbfounded as he threw them up on banks after catching.
So the next trip, he gave the woman two carp. She returned later with fish cakes, cooked by the woman.
They were delicious. In the future he had someone to give the carp.
Just because we don't know, doesn't mean other people don't know.