How do fish swim? *PIC*

Hey nothing to do with my pet bird, but I was talking to Paul about fish and how they swim… He commented that they do it by pushing off the core of spinning vorticies…these vorticies are also made in play by dolphin, quite amazing really they swim at a burst and flick their tail just right to create a vortex and the dolphin then swims up to it and blows a bubble for effect to reveal the flow in the vortex… URL for dolphin info -