Sculling fins of pike allow fish to compensate for tiny variations in current by rotating from within the body.

“Not all fish have adopted a life of speed. Those living in mid-water or along the shores have different problems and requirements, but for them too, the acquisition of a swim-bladder has had a potent effect on structure, for it has freed their body fins for all kinds of purposes. Those of a pike have become elegant filmy sculls, rotating slowly back and forth from a joint within the body, so that the fish can compensate for the tiniest variation of current and hang above a rock as though it were suspended from an invisible wire. (Attenborough 1979:120)

Last Updated August 18, 2016