'Granddad': The Longest-Living Aquarium Fish Euthanized Due To Failing Health

The world's oldest aquarium fish known as "Granddad" was euthanized because of failing health. Granddad was a lungfish in his mid-90s. Bridget Coughlin, the aquarium president, announced the death of the longest-living fish in a zoological setting last Monday. He was seen by over 104 million people in Shedd Aquarium in Chicago since 1933. He was acquired from Aquarium in Sydney, Australia, and joined other lungfish in Shedd.

Rest in Peace Granddad. https://t.co/UYGlnyyknu

— AnimalPlanet (@AnimalPlanet) February 8, 2017

Coughlin said that for a fish that spent much of his time imitating a fallen log, he sparked curiosity, excitement and wonder among guests of all ages who would hear his story and learn about the incredible biology that makes his species a living fossil and one of the oldest living vertebrate genera on the planet. Granddad was known for love of leafy greens and had a penchant for "Earthworm Wednesdays," according to Fox News.

#Bundaberg researchers hope to unlock DNA secrets from Granddad the lungfish, the longest-living fish in captivity https://t.co/bgsK4dttZD pic.twitter.com/LvSUFNdVk3 — ABC Wide Bay (@abcwidebay) February 7, 2017

Granddad was euthanized on Sunday because of failing health linked to aging. He stopped eating and the officials in aquarium examined the fish. They found that Granddad has organ failure and his condition was associated with his geriatric age.

The Shedd Aquarium stated that lungfish could live up to more than 100 years old and are protected species in Australia. It existed for nearly 400 million years, and based on the fossils, they have remained unchanged for more than 100 million years.

Lungfish is also called salamander fish, which belongs to the subclass Dipnoi. It is a freshwater fish and known for his ability to breathe air and a well-developed internal skeleton. It can be found in Australia, South America and Africa.