Fiona is a hippopotamus born at the Cincinnati Zoo and Botanical Garden in Cincinnati, Ohio, United States, on January 24, 2017. The first Nile hippo imaged on ultrasound pre-natally, and the first born at the zoo in 75 years, she was born prematurely and cared for with the assistance of the Cincinnati Children's Hospital.^[2]

Fiona's parents are Henry^{[lower-alpha 1]} and Bibi. She is the first Nile hippo to be born at the Cincinnati Zoo in 75 years, and the first of the species to be scanned in the womb using ultrasound. She was born six weeks premature on January 24, 2017, with a birth weight of 29 pounds (13 kg); the recorded range of birth weights for the species at that time was 55–120 pounds (25–54 kg).^[4][5] She was unable to stand and required bottle feeding with milk from her mother, supplemented with infant formula.^[6] This was the first time a hippopotamus had been milked and the milk analyzed.^[7] The following month, while teething, she began refusing her bottle and became dehydrated; a catheter for the delivery of intravenous fluids was inserted with the assistance of members of the vascular access team at Cincinnati Children's Hospital.^[5][7][8] The preemie team had previously sent the zoo a care package for her.^[9]

Zoo staff named the baby hippo Fiona because her ears resemble those of the Shrek character.^[10] Fiona took her first steps on February 5,^[6][9] weighed 275 pounds (125 kg) by May 31, when she was introduced to the media,^[11] and by June had reached a normal weight of 317 pounds (144 kg);^[12] by the time she was six months old, she weighed over 375 pounds (170 kg),^[13] and in late August, 451 pounds (205 kg).^[14] On her first birthday, January 24, 2018, she weighed more than 655 pounds (297 kg).^[15] By December 26, 2018, she weighed slightly over 1,000 pounds (450 kg);^[16] on her third birthday in January 2020, 1,300 pounds (590 kg),^[17] and on her fourth birthday in 2021, 1,600 pounds (730 kg).^[18]

An 18 year old male hippo named Tucker was moved from the San Francisco Zoo to the Cincinnati Zoo as part of the Association of Zoos and Aquariums' Hippo Species Survival Plan. The move has Tucker being slowly introduced to the Fiona/Bibi duo with hopes that Tucker would be a suitable mate for Bibi.^[19] On August 3, 2022 Fiona's half-brother Fritz, the son of Tucker and Bibi, was born at the Cincinnati Zoo.^[20]

The Fiona Show was launched on Facebook in August 2017.^[14] Saving Fiona, a children's book about her written by the zoo's director, Thane Maynard, was published in June 2018.^[7][21][22] A video posted on social media by the zoo went viral,^[21] as did a couple's photographs of Fiona watching them get engaged in October 2017.^[23][24] In August 2018 a mural of Fiona was unveiled in downtown Cincinnati; Lucie Rice won the contest to design it.^[25]

Fiona appeared in Cincinnati Ballet's December 2018 production of Nutcracker, played by a 6 ft 4 in (193 cm) dancer, and "stole the show".^[26][27]

Fiona has been used to predict the result of the Super Bowl each year since her birth, by choosing between enrichment items with the two teams' emblems. She chose the winning team in 2018, chose wrong in 2019, and in 2020 vomited on the item representing the Kansas City Chiefs, who would win that year.^[28]

Illustrator Richard Cowdrey has written two books about Fiona, including a Christmas book, A Very Fiona Christmas.^[29]