What does a fish look for in a leader? No doubt a nice fishy smell is important, and maybe a sense of direction too, but the overriding factor happens to be something much simpler, and indeed simple enough for a robot to mimic. Our old friend Maurizio Porfiri and a colleague from New York's Polytechnic Institute have shown that a fish-bot will quickly attract live followers if it has a nice, fluid swimming motion. When the stroke is just right, real fish will pull up alongside and visibly relax their own motion to conserve energy, just like geese flying at the rear of a 'vee' formation. It's hoped that, in the future, robots might be used to guide endangered fish populations away from oil spills and other calamities, in much the same way as battery-powered leaders have guided humanity since the dawn of time (allegedly).