A structure that allows the fish to pass over an obstacle in the river such as dams and thus, helps it to migrate is called a fish ladder.
The fish ladder is mostly constructed in the form of small steps and the fish can swim and leap around these steps and reach onto the other side of the barrier.
The fish ladder can of various types but its main purpose is to facilitate the migration of the fish that is hindered due to the building of artificial barriers such as dams.
