The Kaikyokan aquarium in Japan addresses a sunfish's health decline by introducing cardboard cutouts of human visitors, which lifts the fish's spirits and restores its health after a period of isolation.
Japanese Aquarium Brings Sunfish Comfort with Cardboard Human Companions

Japanese Aquarium Brings Sunfish Comfort with Cardboard Human Companions
A social sunfish at a Japanese aquarium receives cardboard human figures in a bid to alleviate its loneliness during renovations, leading to a remarkable recovery.
The Kaikyokan aquarium in Shimonoseki, Japan, has taken social innovation to an unexpected level, providing companionship to a lonely sunfish during a temporary closure for renovations. The aquarium's staff noted the sunfish seemed to suffer from health issues after its human audience was no longer present, leading them to introduce cardboard cutouts of human faces displayed alongside uniforms in its tank. The initiative was described as a "last resort" to remedy the fish's declining condition.
After the aquarium's closure in December, the sunfish exhibited distressing behaviors, including refusing to eat jellyfish and rubbing against the tank walls. Initially thought to be experiencing parasitic or digestive issues, staff member Mai Kato suggested the sunfish might be feeling isolated without visitors. In a heartening turnaround, the aquarium reported the sunfish showed significant improvement soon after the cardboard figures were added, expressing joy by "waving its fins."
This sunfish, which is about 80 cm (31 inches) long and weighs nearly 30 kg (66 lbs), is known for its curious nature, often swimming towards visitors. Following the introduction of the cardboard figures, the aquarium observed an uplifting change in the fish's behavior, and it was even seen displaying happier movements shortly afterward. The aquarium took to social media to share the news, evoking a wave of public support as many users reminisced about their own encounters with the personable fish and expressed their eagerness to return once renovations were complete.
This is not the first instance of an aquarium finding inventive solutions for its inhabitants. During the pandemic, a Tokyo aquarium organized video calls for its eels in response to similar concerns of animal loneliness due to the lack of human interaction. These creative approaches exemplify the deep commitment Japanese aquariums have towards enhancing the well-being of their animals, often turning to unique methods to create a more engaging environment.