Hair, nails, and horns, all made up of keratin, are some of the hardest and most resilient structures in animals. Inside zebrafish cells, keratin plays a distinct role, giving them the strength they need to move together as a coherent tissue while modulating the driving forces behind their movement during early development. But what happens when keratin is missing? A new study from the Institute of Science and Technology Austria (ISTA), published in Nature Communications, reveals how crucial this protein is for life itself.