the world's largest fishtank

...is in the Okinawa Churaumi Aquarium in Japan....the main tank called the 'Kuroshio Sea' holds 7,500-cubic metres (1,981,290 gallons) of water and features the world's second largest acrylic glass panel, measuring 8.2 metres by 22.5 metres with a thickness of 60 centimetres.

whale sharks and manta rays are kept amongst many other fish species in the main tank.