We can't reveal all our secrets, but we can tell you this much: behind the scenes, each virtual fish is really a fish-shaped collection of triangles, as shown at the right.

Each of the triangles is given a new position in 3d space several times per second, which creates the illusion of motion, and then each triangle is replaced with an image of scales, which gives the illusion of... well, a fish.

More than that, we're not at liberty to divulge.