Fish Tank is a functioning aquatic environment designed by MAD Architects, one of China’s leading contemporary practices, led by Ma Yansong. Exhibited in 2004 at the first Architectural Biennial Beijing, the piece is an unconventional and provocative reimagining of standard fish tanks. Ma draws parallels between the spatial confines to which goldfish and humans are subjected, pointing out the way both inhabit enclosed boxes. Fish Tank suggests an alternative to generic, mass-produced cubes by deforming the standard volume, softening its edges, and blurring interior and exterior. MAD Architects developed the complex geometries by analysing the swimming movements of fish. The final form, fabricated in resin, is an elegant and ambiguous habitat. One of the firm’s earliest works, Fish Tank displays at a smaller scale many attributes found in later building projects, such as sensual curves, fluid organisation, and the balancing of natural and technological elements.