On occasion, a work has a reason for characters to breathe a liquid rather than the normal air. This has been accomplished with fluorocarbon liquid for medical purposes, and has been proposed with other theoretical substances to help with crushing pressures or high-g forces.
Super Not-Drowning Skills
is when a character is able to breathe ordinary water for no explicable reason. May be a component in an Artificial Gill
Anime and Manga
- In Neon Genesis Evangelion the cockpits of the titular Mecha are filled with a fictional oxygenated liquid called LCL which is required for the pilot to mentally sync with an Evangelion, as well as providing direct oxygenation of their blood, and dampening the impacts from battle. Once the cockpit is flooded the LCL is ionized, bringing its density, opacity, and viscosity close to that of air.
- The Abyss features a character using liquid breathing to dive thousands of feet without compressing. The Abyss also features a scene with a rat submerged in and breathing fluorocarbon liquid, filmed in real life, not special effects.
- Mission to Mars: The ship that Jim gets into to fly to where the Martians ended up has some sort of breathable liquid in it.
- In David Brin's Uplift series the Streaker, a starship crewed primarily by uplifted dolphins, is largely flooded with "oxywater" that the neo-fin crew can breathe without periodically leaving their stations to come up for air. They strongly prefer air though.
- The Forever War describes liquid immersion and breathing in great detail as a key technology to allow space travel and combat with acceleration up to 50 G.
- In The Lost Symbol by Dan Brown, Robert Langdon (the protagonist) is completely submerged in breathable liquid mixed with hallucinogenic chemicals and sedatives as a torture and interrogation technique by Mal'akh (the antagonist). He goes through a near death experience when he inhales the liquid and blacks out, losing control over his body, but is soon revived.
- Hal Clement's 1973 novel Ocean on Top portrays a small underwater civilization living in a 'bubble' of oxygenated fluid denser than seawater.
- Ben Bova's novel Jupiter features a craft in which the crew are suspended in a breathable liquid that allows them to survive in the high pressure environment of Jupiter's atmosphere.
- In Th Hall Of The Mountain King, one of the stories in the Man-Kzin Wars series features a Tnuctipun pilot encased in a capsule of breathable fluid to protect him (and his normally air-filled lungs) from high-G maneuvers.
- In an episode of Eureka, Sheriff Jack Carter is submerged in a tank of "oxygen rich plasma" to be cured of the effects of a scientific accident.
- In season 1, episode 13 of Seven Days chrononaut Frank Parker is seen breathing a hyper-oxygenated perfluorocarbon liquid that is pumped through a sealed full body suit that he is wearing. This suit and liquid combination allow him to board a Russian submarine through open ocean at a depth of almost 1000 feet. Upon boarding the submarine he removes his helmet, expels the liquid from his lungs and is able to breathe air again.
- The aliens have (stolen) human bodies and stay inside space suits filled with an oxygenated liquid that allows them to breathe.
- Played With in the episode "Ordeal". Aliens kidnap Paul Foster and force him to breathe the liquid so he can survive being transported to the alien home world, but it turns out to be Only A Dream.
- Seven Days: The three aliens that crashed at Roswell in 1947 are kept in alien jars at Neverland. One is still alive, and it can apparently breathe the liquid since it's not hooked up to any tubes.
- Hollow Earth Expedition supplement Mysteries of the Hollow Earth. In the seas around the Sunken City can be found crystal orbs that, when broken, oxygenate the surrounding water enough for land creatures to breathe it.
- In Sword of the Stars the Liir use a hyper-oxygenated liquid on their ships. The ceremony for joining the Black Swimmers includes a ritual "drowning" in the substance.
- X-COM: Terror from the Deep. "Aquanauts" fighting deep ocean conditions breathe a dense oxygen-carrying fluid.
- In the EVE Online Universe, pilots in capsules (escape pods that function as the control center for the spacecraft) breathe an oxygen rich, nano-saturated, breathable glucose-based suspension solution
- In an episode of Metalocalypse, the other members of the band submerge guitarist Toki in a "liquid oxygen isolation chamber" while recording an album in the Mariana Trench.
- There have been some experiments in liquid breathing using perfluorocarbon, which has a higher oxygen capacity than blood. It requires mechanical assistance to circulate the fluid, and often surgery to ventilate it, but liquid breathing has been used occasionally to help premature infants and adults with ARDS breathe since the 1990s.