Gossiping and socializing are not generally associated with schools of fish. However, it turns out that fish are not only capable of making "friend" groups, but they prefer to learn from and communicate with those in their particular social group.
A recent study conducted by researchers from University of St. Andrews, Anglia Ruskin University, and Canada's McMaster University recorded the activity of a group of 80 three-spined sticklebacks over the course of six weeks. After being initially divided into two groups, the fish were then placed into small mixed groupings of 10. Researchers found that the fish who had been in a tank together previously tended to group together again.