The Aquarium is housed under the Mappin Terraces. The space had been set aside for an aquarium from 1913 when the Terraces were laid out, but detailed planning was deferred by war until 1921-22. Briefs were provided following visits to aquariums in Amsterdam, Antwerp, Brussels, Berlin and Dresden. It was built 1923-24, brief by E G Boulanger, Curator of Reptiles; John James Joass, architect; Alexander Gibb and Partners, engineers; J Jarvis and Sons Limited, building contractors; Joan Beauchamp Procter, rockwork design; cost around £55,000. Refaced to west 1951, and to east 1965, Franz Stengelhofen, architect. Grade II listed. The Aquarium closed on 22 October 2019. Some animals were moved to a new aquarium at Whipsnade Zoo, while others were set to be housed in a new corals exhibit in the B.U.G.S. building in 2020.
Electricity was installed in the rest of the Zoo when the Aquarium was built.
The Animal Hospital and Pathology Laboratory (occupied by the Institute of Zoology's Department of Veterinary Science) was built as a 'Sanatorium and Quarantine Station' to replace the sanatorium north east of the Bird House (see Prosectorium). The siting is deliberately remote from the Zoo's animal houses. On the ground floor there are offices, an operating theatre, an X-ray room, a food preparation area and animal dens around the west and south sides leading to outdoor cages in a walled yard. The first floor has offices, laboratories and large cages. Built 1955-56, Franz Stengelhofen, architect.
Animal Adventure (formerly called the Ambika Paul Children's Zoo) opened in 2009 and is an area aimed primarily at children, featuring playgrounds and a water fountain. Many of the animals in Animal Adventure are domestic animals such as sheep, donkeys, llamas, alpacas, goats and ferrets, as well as rare breeds such as silkie chickens, rex rabbits and kunekune pigs. Exotic species on display include yellow mongooses, crested porcupines, aardvarks, prairie dogs, ring-tailed coatis and one of the zoo's two groups of meerkats. The meerkat enclosure features a tunnel that children can crawl through until they reach a see-through dome that allows them to see directly into the enclosure.
The Amphitheatre was made for presentations and events. The stage and terraced seating were laid out on a lawn that had earlier been the site of the Chimps' Tea Party. South if the amphitheatre there is an iron pergola dating to the late 19th/early 20th century. Built 1982-1985, initial design by John Toovey, architect and Anthony Hunt Associates, engineers. Superstructure donated by Bovis Coverspan Limited and designed by Ove Arup and Partners (Brian Forster). Re-erected 1990 after collapse in a storm. It was destroyed by storm damage on 28th October 2013.
