Goldfish swim in the “BonBorium” installation during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. Some 5,000 goldfish are on display with the various latest techniques at the art exhibition, which will be opened to the public between 11 July to 23 September. (Photo by Kiyoshi Ota/EPA)

Goldfish swim in the “BonBorium” installation during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. (Photo by Kiyoshi Ota/EPA)

A young Japanese woman dressed in yukata looks at goldfish swimming in the “Ohoku” installation as she poses during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. (Photo by Kiyoshi Ota/EPA)

Goldfish swim in the “Reflectrium” installation during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. (Photo by Kiyoshi Ota/EPA)

A young women wearing the summer Kimono, “Yukata” watches goldfishes during the press preview of “Eco Edo Nihombashi Art Aquarium 2014” exhibition in Tokyo on July 10, 2014. The two-month-long goldfish exhibition will starts July 11. (Photo by Toshifumi Kitamura/AFP Photo)

Women wearing the summer Kimono, “Yukata” watch goldfishes during the press preview of “Eco Edo Nihombashi Art Aquarium 2014” exhibition in Tokyo on July 10, 2014. (Photo by Toshifumi Kitamura/AFP Photo)

A young woman wearing the summer Kimono, “Yukata” watches the goldfishes during the press preview of “Eco Edo Nihombashi Art Aquarium 2014” exhibition in Tokyo on July 10, 2014. (Photo by Toshifumi Kitamura/AFP Photo)

A young Japanese woman dressed in yukata looks at goldfish swimming in a fish tank as she poses during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. (Photo by Kiyoshi Ota/EPA)

A young Japanese woman dressed in yukata looks at goldfish swimming in the “Reflectrium” installation as she poses during a press preview of the “Art Aquarium” exhibition as part of the “Eco Edo Nihonbashi 2014” summer event at Nihonbashi Mitsui Hall in Tokyo, Japan, 10 July 2014. (Photo by Kiyoshi Ota/EPA)