Developing zebrafish embryo

Our understanding of how animals grow from a single cell to billions of cells has benefited tremendously from the easy-to-visualize nature of zebrafish embryos. This video begins roughly two hours after a zebrafish egg has been fertilized and covers approximately 24 hours of the embryo’s life. In less than a day, the embryo will progress through dramatic changes in shape as cells move and specialize in a process called gastrulation. By 9 hours after fertilization, the rudimentary brain will start to thicken, and by 12 hours, premature eyes form. Muscular twitches begin and exaggerate from 20 hours onward before the heart even starts beating properly. Within three days from the start of its one-cell journey, the fish will reach the length of a sesame seed before swimming in search of food.

Video by Dr. Andrei Kobitski, Dr. Jens Otte and Dr. Johannes Stegmaier, Karlsruhe Institute of Technology, Germany.