The Horniman Museum's aquarium is one of London's oldest surviving aquaria. Frederick Horniman is said to have been inspired to construct an aquarium in the Museum after viewing the Horniman Aquarium at the Great Exhibition site.

The Aquarium was founded in 1903 under the supervision of eminent zoologist and ethnographer Alfred Cort Haddon (1855-1940). Haddon was a correspondent of Phillip Henry Gosse (1810-1888), the Victorian naturalist consulted by Charles Darwin. Gosse set up the first marine aquaria in Britain and also wrote the first descriptive catalogue of British marine invertebrates.

In July 2006 a new modernised aquarium opened at the Museum. Located in the basement, it contains 15 vibrant displays including among others, a Fijian Reef, a Tropical Rainforest, Mangrove and UK rock-pool display.

In the development of these displays, the aquarium team worked with both national and international conservation and research organisations including the Marine Aquarium Council (MAC), the Marine Biological Association (MBA) and the Iwokrama project in Guyana.

A key part of the aquariums ethos is the development of strong research collaborations with universities and aquariums, nationally and internationally. We are currently focusing our research on the reproductive biology of jellyfish and coral.