Gudgeon is a small fish that is often overlooked, but it can be a great addition to any aquarium. This guide will provide an overview of the gudgeon, its habitat, diet, and care requirements. You'll
From Wikipedia
A gudgeon is a socket-like, cylindrical fitting attached to one component to enable a pivoting or hinging connection to a second component. The second component carries a pintle fitting, the male counterpart to the gudgeon, enabling an interpivoting connection that can be easily separated. Designs that may use gudgeon and pintle connections include hinges, shutters and boat rudders.