Groups of genetically identical fish follow different behavioral paths as they mature

Schooling fish have long fascinated us with their mesmerizing collective movements and seemingly perfect coordination. But a new study on clonal mollies suggests that this behavior is not innate. During their first days of life, the fish still display distinct individual behaviors, and it is only around one month of age that they begin to form cohesive shoals, developing the coordinated movements characteristic of the group. However, several shoals of genetically identical clones begin to behave differently after a few weeks.