Shoal Thing moves around like a school of fish and likes to play.
Glide a finger across the screen and theyll scram like its a predator. Press with two and theyll circle in like theres food around. Tap with three fingers to turn on neighbour lines and transform the individual fish into Shoal Thing.
The free version of the app lets you be a predator. The full version (available by in-app purchase) enables all three features.