Fluid (known in Japan as Depth) is a music video game developed by Opus and published by Sony Computer Entertainment for the PlayStation.

The game's concept is an interactive sound lab which allows the player to create dance and electronic music.

The player character, a dolphin, goes through many stages in order to unlock more sounds, some of which including "Abyss Lair" and "Jungle Reef".

Several tracks can be mixed at once, controlling speed, pitch, frequency and modulation with a series of coloured crystals.

Oli Yarwood of Eurogamer appreciated the game for its surreal nature and soundtrack, comparing it positively to Harmonix's Frequency and Amplitude (also published by Sony).