Glassfish appear to coordinate by copying one nearby neighbour at discrete moments rather than averaging the movements of the whole local group.
Researchers tracking Danionella cerebrum found that an individual randomly selects a nearby fish and aligns with its movement during precisely timed windows following that neighbour’s turn. Virtual-reality experiments reproduced the predicted responses using simulated fish. Repeated pairwise interactions are sufficient for schools to form, fragment and reorganise, producing coherent group behaviour from sparse, rapidly changing social connections.
