Micro-aquarium

Tropical fish are swimming in a micro-aquarium.
This micrograph shows Ag-In-Sb-Te alloys, the recording layer of a DVD-RW(Digital Versatile Disc Rewritable), taken by a FE-SEM in the low voltage BSE(Backscattered Electron) mode.
The tropical fish are actually recording marks where a phase change from a crystalline to an amorphous structure has occurred due to strong laser beam irradiation. To read data on the DVD, the reflection of a weak laser beam converts the digital data array to a series of 0's and 1's. The writing process generates multiple recording marks that become our tropical fish in this micro-aquarium.