The Belle Isle Aquarium is a public aquarium located in Belle Isle Park in Detroit, Michigan. Designed by noted architects George D. Mason and Albert Kahn, it opened on August 18, 1904, and was the oldest continually operating public aquarium in North America when it closed on April 3, 2005. The aquarium reopened to the public on August 18, 2012, and is now run entirely by Belle Isle Conservancy, a 501(c)3 non-profit partner to Belle Isle park. The 10,000-square-foot (930 m2) historic building features a single large gallery with an arched ceiling covered in green glass tile to evoke an underwater feeling.

A public aquarium (pl. aquaria) or public water zoo is the aquatic counterpart of a zoo, which houses living aquatic animal and plant specimens for public viewing. Most public aquariums feature tanks larger than those kept by home aquarists, as well as smaller tanks.