A previous photo showing ocean sunfish at Hirtshals Aquarium in Denmark. CNN
In an unexpected turn of events, a lonely sunfish at a Japanese aquarium became the focus of a unique experiment aimed at improving its health. This all began when staff at the Kaikyokan Aquarium in Shimonoseki, Japan, noticed that their sunfish began to act strangely after the aquarium closed for renovations in December 2024.
The sunfish, known for its curious nature, had been thriving and swimming near the front of its tank when visitors were around. However, when the crowds stopped coming, the fish suddenly lost its appetite and began rubbing against the tank, showing signs of distress. Despite the staff's best efforts to diagnose the issue, nothing seemed to work, and it wasn’t clear what was causing the fish’s sudden decline in health.
The breakthrough came from a staff member who proposed an unusual idea: maybe the sunfish was feeling lonely without the visitors. While this suggestion initially seemed far-fetched, the team decided to give it a try. They attached the uniforms of the staff members to the glass surrounding the fish’s tank, as a form of makeshift “people” to keep it company.
To everyone’s surprise, the next day, the sunfish appeared much healthier and more active, swimming around as it had before. The aquarium shared a picture of the fish, now swimming contentedly near the cardboard cutouts of faces and staff uniforms hung up on the glass. Staff members also began waving at the sunfish, further attempting to cheer it up.
Though it might sound unbelievable, the aquarium explained that this particular sunfish had always shown curiosity toward people, often swimming to the front of its tank whenever visitors were around. The sudden lack of human presence seemed to have caused it distress, leading the fish to stop eating and begin rubbing its body against the tank. Staff suspected that the fish might have developed digestive issues or possibly been affected by parasites.
This unique solution is not the first time an aquarium has turned to creative methods to help animals adjust to life without visitors. In 2020, during the COVID-19 pandemic lockdown, Tokyo’s Sumida Aquarium came up with a similarly innovative idea. The aquarium asked volunteers to FaceTime with their 300 spotted garden eels, which had become shy and uncooperative without visitors. This allowed staff to check on the health of the eels while also providing them with some human interaction.
As for the sunfish, its turnaround is a testament to the unexpected ways in which animals can be affected by the absence of human presence, and how innovative solutions can sometimes solve problems in ways that might seem strange at first.
