As part of WCS, the aquarium's mission is to save wildlife and wild places worldwide through science, conservation action, education, and inspiring people to value nature.

The New York City government had proposed converting Castle Garden, a former military fort and immigrant-processing station in Battery Park, into an aquarium in 1891.

[2] The following February, the New York State Legislature passed a bill allowing the city government to create an aquarium within Castle Garden.

[3][4] Julius F. Munckwitz Jr. drew up preliminary plans for an aquarium, which he presented to New York City's board of park commissioners in mid-1892.

[16] In its early years, the New York Aquarium at Castle Garden typically had more visitors during the summer, and Sunday was the busiest day of the week.

[28] By January 1911, officials instead planned to expand Castle Garden,[29][30] adding semicircular wings to the west and east for over $1 million.

The plans included constructing a third story for workrooms and laboratory space, installing tanks behind the building, adding a new mechanical plant in the basement, and covering the facade with a gray cement finish.

[58][59] The New York City Planning Commission allocated 5 acres (2.0 ha) of parkland to the new aquarium,[60] and construction commenced on October 24, 1954.

[73] In September 2011, the aquarium named its new electric eel Wattson,[74] and in March 2012, it launched a sea horse breeding program.

[76] In March 2007, the winning design by firms WRT and Cloud 9 was selected, which featured an enclosure resembling a whale over the aquarium.

[77][78] However, in March 2008, that concept was scrapped due to concerns over the cost of the design and the practicality of constructing future exhibits under the enclosure.

[80] The massive 784,000-US-gallon (2,970,000 L), 57,000-square-foot (5,300 m2) exhibition, Ocean Wonders: Sharks!, was originally scheduled to break ground in November 2012 and open in 2015.

[81] However, the New York Aquarium was significantly damaged by Hurricane Sandy in October 2012, which severely flooded the facility and shut down power.

[84][85][86] The aquarium closed for four months starting in March 2020 due to the COVID-19 pandemic in New York City, which shuttered almost all businesses citywide.

With the reopening of the aquarium in July 2020, a new exhibit called Spineless, dedicated to invertebrate marine species, was opened.

[88] As of 2018[update], the New York Aquarium consists of five exhibits: Aquatheater; Conservation Hall; Sea Cliffs; Spineless; and Ocean Wonders: Sharks.