Fin rays stiffen the fins to provide better stability for the fish.

Also, fin rays may be moved individually by muscles, so undulating movements of the fins are possible.

The ray fins are also subject to changes in its structure, that provide other important functions besides swimming and displacement stability. For example, the dorsal fin of the fishes from the family Echeneidae has been modified, to become the suctorial disc that allows fixed to the other animals with whom they live, such as turtles and sharks among others. Similarly, there are changes in the anal fin in Cyprinodontiformes to form the copulatory organ of males.

the ray fins benefits for make a sharp or strong fins that cause fish stable and move in water column.