As an animal model, the zebrafish offers many advantages that save researchers time and money. Uri Manor/NICHD via Flickr, CC BY-SAScientists have relied on animal models as an alternative to testing on human tissues and cells for decades. But not just any organism can adequately model how human cells behave. Researchers take into account how quickly the organism can mature, how many offspring it can produce and how often it can reproduce. When studying genetics and developmental biology, one of