The aquarium was named after Karel Willem Benjamin Van Kleef who was Dutch but resided in Singapore in the 19th and early 20th century. When Van Kleef died in the Netherlands in 1930, he donated a sum of $160,000 (equivalent to $8.985 million in 2014), his entire fortune, to the Singaporean government. After some considerations, it was decided in 1933 that the best option was to build an aquarium. In 1935, a site on Fort Canning Hill between Tank Road and River Valley Road was chosen as the site for the aquarium. Construction started in 1940, but it was interrupted by the Japanese invasion during World War II. Construction restarted in 1953, supplemented with funds from the city council. The aquarium eventually opened on 8 September 1955, 25 years after Van Kleef's death.