Zebrabow embryos express random combinations of red, green, and blue fluorescent proteins, revealing a spectrum of unique hues. These same hues can be used to ‘barcode’ individual stem cells to track their birth and contribution to tissues as the embryo grows–all cells of the same hue were produced from one stem cell’s divisions. The Zebrabow system allows for long-term tissue lineage analysis, because the fluorescent proteins will be expressed in each cell throughout the lifespan of the zebrafish. Thanks to Jonathan Henninger for this piece, a 6th year graduate student in the Biological and Biomedical Sciences Program.