Fish School Simulator (2D)

This 2D top-down simulator reimplements a schooling fish tank: dozens of fish continuously apply separation, alignment and cohesion to their nearest neighbors, producing the same swirling, organic group motion seen from above a real school. Click the water to drop in a predator and watch the school scatter and panic in proportion to how close it gets, or shift-click to drop food and pull the school into a tight feeding cluster; sliders let you rescale the fish count, the strength of the three schooling rules, and how sharply each fish can turn, while Calm and Panic mode presets swap in a whole different balance of behavior at once.