Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists have pioneered the animal husbandry of jellyfish and it was the first to successfully care for and display a great white shark. The organization's research and conservation efforts also focus on sea otters, various birds, and tunas. Seafood Watch, a sustainable seafood advisory list published by the aquarium beginning in 1999, has influenced the discussion surrounding sustainable seafood. The aquarium is the home of the current oldest living sea otter, Rosa, and the birthplace of Otter 841.

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.