The ventral fin is a type of fin located on the underside of a fish's body. It plays a crucial role in stabilizing the fish while swimming and helps with maneuverability. In some species, the ventral fin can also assist in braking and turning. In addition to fish, the term "ventral fin" can apply to other aquatic animals, such as certain species of sharks and rays. The structure and function of ventral fins can vary significantly among different species, reflecting their unique adaptations to their environments.