The intestine is home to trillions of diverse microorganisms. How do our bodies interact with and manage such a complex community? Duke graduate student Briana Davis and colleagues in professor John Rawls' lab are turning to zebrafish for clues. Nearly twice the length of a grain of sand, this 1-day-old zebrafish will develop a digestive system quite similar to our own. It was genetically engineered for certain tissues, like the intestine, to emit green light. Using these ‘green guts,' the lab hopes to visualize intestinal responses to microbes to better define how animals communicate with the microbial community within.