CINCINNATI — Now a half ton of fun, the Cincinnati Zoo’s famed prematurely born hippo will soon turn 2 years old. The zoo says a variety of activities will celebrate Fiona’s latest milestone. The hippo was born Jan. 24, 2017, at a dangerously low 29 pounds (13 kilograms). Round-the-clock critical care and outside help including from the Smithsonian National Zoo and the Cincinnati Children’s hospital enabled Fiona to not only survive, but to thrive as a social media sensation .