Zebrafish are a favourite research model for scientists to study vertebrate development and tissue regeneration. The skins cells of this particular zebrafish have been labeled with a cool, new fluorescent imaging tool called Skinbow.
Skinbow uniquely colour-codes cells by getting them to express genes encoding red, green, and blue fluorescent proteins at levels that are randomly determined. The different ratios of these colourful proteins mix to give each cell a distinctive hue when imaged under a microscope.
In this image of a tiny piece of zebrafish skin (less than a quarter of a square millimetre) you can see more than 70 detectable Skinbow colors that make individual cells as visually distinct from one another as jellybeans in a jar.