The rock-climbing fish (Beaufortia kweichowensis) adheres to slippery, fouled surfaces and crawls both forward and backward in torrential streams. During locomotion, two suckers can be distinguished.

What is hydrodynamics in fishes?

DPIV reveals hydrodynamic force partitioning among fins. In addition to being functionally versatile, fish fins are highly integrated components of the propulsive system. Fishes can employ multiple fins distributed over the body simultaneously both to produce and modulate swimming force.

What do fish use for locomotion?

Most fishes generate thrust using lateral movements of their body and caudal fin, but many other species move mainly using their median and paired fins. The latter group swim slowly, but can turn rapidly, as is needed when living in coral reefs for example.