Fiona's dad, Henry the hippo, dies at Cincinnati Zoo

After 36 long, happy years, Henry the hippopotamus died Tuesday following complications brought on by an infection, according to the Cincinnati Zoo & Botanical Garden.

The zoo confirmed the news Tuesday in a tweet.

"We're very sad to announce that our beloved Henry has died," the zoo's tweet read.

According to a statement from the zoo, caretakers decided Tuesday to "humanely euthanize" the hippo, who had been struggling with his health for months and had lost hundreds of pounds.

“The blood work from Henry’s last exam gave us some hope that he was on the mend, but his appetite never returned and his condition declined rapidly," said Christina Gorsuch, the zoo's curator of mammals. "Vets and his care team worked tirelessly to keep him comfortable and help him fight this illness."

The 36-year-old father of Fiona began showing signs of illness in July when he stopped eating. This showed to be normal for Henry, based on his records from the Dickerson Park Zoo in Springfield, Missouri, where he lived until he came to Cincinnati in July 2016.

More:Zookeeper: Treatments aren't working for Henry the hippo

After he stopped eating, Henry's caretakers began feeding him antibiotics and pain medication with applesauce and beet pulp. But "nothing – antibiotics, favorite foods, extra TLC – seemed to turn his condition around,” Gorsuch said.

In August and September, Henry seemed to be back to normal. But then things took a turn for the worse.

After running blood tests, veterinarians in  determined Henry was fighting an infection. And despite having some good days, they were outnumbered by the bad.

"He became pickier and pickier until he was barely eating anything and he began losing weight," Henry's caretaker, Wendy Rice, wrote in a blog post Monday. "Additionally, he became more lethargic and less interactive with keeper staff and even his interactions with Bibi and Fiona diminished."

Following another exam Tuesday, and after careful consideration by the vet staff monitoring Henry, the zoo decided to say goodbye to their sweet, gentle giant.

"While our time with him has been short in quantity, no one can deny that his quality of life before becoming ill was exceptional," Rice said. "From meeting, bonding and breeding with his mate Bibi, to becoming a father to charismatic and spirited Fiona, Henry’s days in Cincinnati were filled with sunshine, watermelons, waterfalls and the highest quality of care that can be provided to any animal."