Don’t try this fishy antiaging remedy at home. Researchers have discovered that young poo, teeming with gut microbes from 6-week-old African turquoise killifish (closely related to the bluefin killifish, above), can dramatically prolong the lives of older fish, according to Nature. Killifish live brutally short and efficient lives, sexually maturing in 3 weeks and dying within a few months. Nine-and-a-half-week-old fish that nibbled at young fish poo lived about 40% longer than their peers, and swam as actively as younger fish, even at 16 weeks old, the scientists report in a preprint on bioRxiv. The experiment is reminiscent of studies that aim to rejuvenate the elderly humans and mice with blood transfusions from the young.