Occupying the historic FirstEnergy Powerhouse building located on the west bank of the Cuyahoga River in the city's Flats district, the aquarium, which opened in January 2012, consists of approximately 70,000 square feet (6,500 m2) of exhibition space and features 55 exhibits over 9 thematic concentrations representing both local and exotic species of fish.

A $300,000 gift from the Leonard C. Hanna Foundation financed the construction of a new octagonal wing in 1967 that tripled the aquarium's size and increased its tank capacity from 8,000 to 82,000 US gallons (30,000–310,000 L).

Despite annual deficits experienced during the decade, a city council override of a mayoral veto to increase the admission charges and keep aquarium operations with the museum was performed in 1979.

[4] On April 1, 1986, fish and exhibits were moved to the Cleveland Metroparks Zoo,[3] where they remain today in the Primate, Cat & Aquatics Building.

[5] Although there were competing interests, the driving force behind the project was Jeffrey P. Jacobs, a local developer who envisioned it as being part of the Powerhouse, a complex he owned.

[10] In 2018, the Greater Cleveland Aquarium announced plans to upgrade much of its public space[11] using internal resources and many upcycled materials.

[12] In addition to upgrading animal life support systems, the Aquarium enhanced gallery theming, welcomed more than a dozen new species[13] including weedy seadragons[14] and splitfin flashlight fish, and expanded its annual passholder program.

{9/21/23}) [18] In 2012, Greater Cleveland Aquarium's general manager Tami Brown established a non-profit Splash Fund[19] “to educate and encourage passion about aquatic life and participation in the conservation of fresh and saltwater habitats through sustainable human practices.” In 2019, Splash Fund Board Members include new general manager Stephanie White, Deborah Altman, Bruce Akers, Richard Dorman, Scot Rourke and Trevor Gile.

Monies raised by this nonprofit fund have been used to conduct regular community Adopt-A-Beach cleanups at Edgewater Park, provide schools with demonstrated need access to life science-based educational programs and works to encourage a more robust Northeast Ohio spotted turtle population.