https://www.sciencedaily.com/releases/2019/10/191021094002.htm

The fish in this case aren't actually aquatic animals. They're minute disruptions in the orientations of the molecules that make up solutions of liquid crystals, said Hayley Sohn, lead author of the new study.

But under the microscope, these molecular deformations -- 10 of which could fill the width of a human hair -- certainly look alive. These pseudo-particles can twirl together as a group, shift their motion on a dime and even flow around obstacles when exposed to different electric currents.