Sawfish swim left and right rather slowly, but when they see Wario, they charge at him at a very high speed. Wario gets hit and loses coins if he touches their sword-like beaks, but touching them from any other side only pushes the sawfish away slightly. Touching them from below additionally stuns them for a short time.
Since sawfish are only found in water, where Wario cannot use any of his usual attacks, they are invulnerable. As they can only swim left and right, however, Wario can often move them out of his way by pushing them upwards.