I didn't know until just now that there were aquariums with Whale Sharks in them. This must depict the Okinawa Churaumi Aquarium, as the internet tells me it's the only one in Japan with whale sharks (they don't seem to be "full size", but still 8.8m or 28ft).
https://churaumi.okinawa/en/area/the-kuroshio/kuroshio/