Pectoral fins are the paired fins located on the sides of fish, just behind their heads. These fins play a crucial role in helping fish steer, balance, and maintain stability while swimming. They can also be used for braking and even for some species, like manta rays, to glide gracefully through the water. In addition to their swimming functions, pectoral fins can serve other purposes. For example, some fish, such as catfish, use their pectoral fins to help them navigate through murky waters or to dig in the substrate. Overall, pectoral fins are essential for a fish's movement and survival in aquatic environments.