Built between February 1998 and December 1999, the building was designed by Peddle Thorp architects to resemble a ship moored to the river, and opened in January 2000. The depth of the building however was designed not to be imposing at street level, and extends 7 metres (23 ft) below the surface. At its centre is a World first, 2.2 million litre 'oceanarium in the round' where the spectators become the spectacle to the marine life swimming around them.
The Melbourne Aquarium recently underwent a significant expansion, also designed by Peddle Thorp, and now extends from the Yarra River to Flinders Street. A new entrance was built on the corner of Flinders and King Streets. The expansion features exhibits with king penguins and gentoo Penguins, as well as many other Antarctic fish, a first for Australia. The exhibits also feature real ice and snow to simulate Antarctic conditions, and take visitors on an expedition to Antarctica. The penguins are sourced from Kelly Tarlton's Underwater World in New Zealand.