This is the flat, top-down companion to the 3D Aquarium simulator. Every fish is an independent agent that queries only its nearby neighbours through a spatial grid and combines three flocking forces — separation, alignment and cohesion — with two fish-specific behaviours: fleeing from sharks and steering toward food. Nothing is scripted at the group level; the school, the scattering when a shark charges, and the scramble toward a dropped crumb all emerge from these local per-fish rules.