Fins are important appendages that help fish maintain position, move, steer and stop in water. They are composed of bony spines covered in skin and aid with mobility, stability and maneuverability. The main types of fins are paired (pectoral and pelvic) and unpaired (dorsal, caudal, anal). Each fin type has a distinct function in swimming, turning and balancing. Fins have evolved diverse shapes and forms to help fish survive in their environments.