Embryonic heart of a 3 day old zebrafish. In this transgenic Tg(gata1:GFP) zebrafish, red blood cells are fluorescently-labeled (rendered in red) and a vital dye, BodipyTR reveals the surrounding anatomy (rendered in gray). The data was collected on an LSM 5 LIVE confocal microscope (Carl Zeiss GmbH) at the Biological Imaging Center, Caltech, reconstructed with specifically developed programs, and rendered with Imaris (Bitplane AG). (Image: Michael Liebling and Arian Forouhar, Caltech)