Van Kleef Aquarium was an oceanarium located in Fort Canning Park facing River Valley Road in Singapore. The aquarium was opened in September 1955 and demolished in 1998. The aquarium was named after Karl Willem Benjamin Van Kleef who was Dutch but resided in Singapore in the 19th and early 20th century. Van Kleef donated his fortune to the Singaporean government to build the aquarium after his death. When the aquarium opened it contained 6,500 marine creatures of 180 different species. There were salt water, fresh water and swamp water tanks. The building was fully air-conditioned. 270,000 visitors came in its first year of operation. During the 1970s the average number of visitors was about 400,000 annually. Visitor numbers fell to 248,000 in 1985. The aquarium underwent major renovations from 1986 to 1987. The aquarium was closed during the renovations which cost S$ 750,000. Unfortunately the number of visitors never reached the peak of the 1970s again. In 1991 Underwater World opened on Sentosa island. Most visitors went to the new aquarium. This led to the decision by the Ministry of National Development of Singapore to close the Van Kleef Aquarium in 1991. The building was demolished in 1996.