This facility was opened on 15th of July, 2001 on the banks of Naka river and Houki river, famous for its clear water and ascending sweetfish in Kanto area. It is composed of 「Omoshiro sakana kan （Interesting fish hall）」which exhibit various kinds of freshwater fish, parks, observation tower, 「Osakana fureai station (contact with fish station)」and others. Large tropical fish such as Pirarucu, an ancient fish and freshwater ray fish are swimming around in water tank for exhibition. Also, there is a river model of Nakagawa river exhibiting freshwater fish living in each part of the river. Various freshwater fish of Japan, tropical saltwater fish and rare fish of Japan are also exhibited.
As explained before as one of the characteristics of 「SILICA WHITE」, it locks in calcium hydroxide on a long term basis and simultaneously fills the voids caused by bleeding during the hardening period. Because these chemical and physical effects contribute to make high watertight concrete semipermanently, 「SILICA WHITE」was adopted for this building. The building was awarded the Annual Architectural Design Commendation prize of Architectural Institute of Japan in 2005.
