Gorgeous zebrafish embryo approximately 1 day post fertilization (dpf). The staining pattern isn’t noted in the linked page, but I imagine it is a transcription-factor expressed fluorescent protein pattern, although I cannot be certain. Picture taken by Philipp Keller, Bill Lemon, Yinan Wan and Kristin Branson of the Janelia Farm Research Campus, Howard Hughes Medical Institute.
Image taken from: http://images.nigms.nih.gov/index.cfm?event=viewDetail&imageID=3644












