Methuselah, a female Australian lungfish at San Francisco's Steinhart Aquarium, has always been a favorite with locals. But she has achieved global fame since September 2023, after scientists announced that she was at least 93 years old, making Methuselah the world's oldest living aquarium fish. The title was previously held by Grandad, an Australian lungfish who lived at Chicago's Shedd Aquarium. He was believed to be between 109 and 115 years old when he died in 2017.