Blood Is Squicker in Water

"''Will all great Neptune's ocean wash this blood

Clean from my hand? No; this my hand will rather

The multitudinous seas incarnadine,

Making the green one red.''"

- Macbeth, Act II; scene ii.

One way to show Ludicrous Gibs without breaking the laws of biology is to have a character die in a body of water, thus diluting the blood and causing it to billow out in clouds. As a bonus, this tends to look very symbolic... of nothing in particular.

Of course, if this happens in the open sea, the probability that someone will mention sharks, and their ability to smell a single red blood cell from 6 million light years away, rapidly approaches 1.

Another common appearance is in an Out Damned Spot hand-washing, or a post-carnage Shower of Angst.

In a case of Reality Is Unrealistic, real blood diluted in a large volume of water will actually turn it yellow, the color of blood plasma (the liquid portion of the blood), not pink/red. However, for small amounts, the picture above is accurate.

One of the Bloody Tropes. A related phenomenon above the waterline is Pink Mist. Can be a symptom of Gorn.

A Bath Suicide invokes this trope. Compare Blood Bath, where circumstances see blood substituted for water.

If you were looking for The fanfic "blood in the water", it's here.

Anime & Manga
"Robin: Well, he's not dead, or the water would be turning red."
 * In the Yakuza arc of Black Lagoon, the resident Jerkass gets his hands sliced off (with a sword, in a modern-day setting) and is held underwater to bleed to death. Yes. He had it coming, though.
 * The ending sequence of Higurashi no Naku Koro Ni begins by showing blood which has just fallen into the water.
 * A Running Gag in One Piece is Robin casually pointing out this trope whenever it seems as though someone might be killed particularly messily underwater, much to the discomfort of everyone in earshot.


 * In an early filler episode of D Gray Man, Kanda fights another swordsman in a pool of water and gets slashed across the chest. The last shot of the episode is of his blood spreading through the water around him.

Film

 * The finale of Rush Hour.
 * Pretty much every death in Jaws, for obvious reasons.
 * Dieter Stark's death at the hands (claws?) of the compys in Jurassic Park: The Lost World. Also, Robert Burke's death has parts of this, as you see his blood flowing down the waterfall.
 * Psycho, the shower scene (chocolate syrup!).
 * The Golden Voyage of Sinbad. After Prince Koura is mortally wounded while in the Fountain of Destiny, the Fountain's waters turn red to symbolize his blood loss.
 * The finale of The Omega Man, where Charleton Heston dies in a Christ-like pose in a blood-filled fountain. His blood is also the world's salvation, to really push the symbolism.
 * The end of Sympathy For Mr Vengeance has one of the characters kill another in a shallow river and then drag him ashore (it's a beautiful scene)
 * Occurs in the film Godzilla VS Mechagodzilla. In the fist battle between Godzilla and his robot counterpart, Godzilla is shot several times by Mechagodzilla and falls into the ocean. The ocean turns red with Godzilla's blood but,
 * Saving Private Ryan has many soldiers die before reaching shore as bullets hit them below the waterline. By the end of the scene, the entire surf is red.
 * Several movie versions of The Great Gatsby do this with
 * Several times in The Beach.
 * In Fool's Gold, an enemy scuba diver is sucked into a current in an underground cave that feeds a geyser. When the geyser erupts, it's red with his blood.
 * is shot in the bath in Road to Perdition.
 * Tony Montana's death at the end of Scarface.
 * All Piranha films.
 * In The Godfather Part II, a character commits Bath Suicide, Roman fashion. We only see the aftermath, including liberal helpings of blood on the walls for good measure.
 * In Black Swan, blood mysteriously drips into the bathtub over Nina's face as she submerges herself, right before one of the film's many Jump Scares...but it might not have really happened.
 * The Crazy 88 fight in Kill Bill ends up with several of the Mooks, and Johnny Mo, lying dead in the restaurant's now-crimson ornamental water features.
 * When a slasher movie has a name like The Pool, it is to be expected.
 * Sunset Boulevard averts this by having Bloodless Carnage.
 * Discussed towards the end of Get Him to The Greek, when the burned out and increasingly suicidal rock star Aldous Snow breaks his arm diving into a pool from a hotel roof, then has a tearful conversation with Aaron about how destructive his lifestyle is and that it's not working for him. All the while astute viewers may notice that in the background the pool is getting increasingly bloody. Aaron mentions it at the end of their conversation and asks Aldous if he's ok. Aldous shrugs it off, saying that a little blood looks like much more than it really is in water.

Gamebooks
"He surfaces, sword in hand, but is pulled under again and this time he does not reappear. A trail of bubbles and a patch of red water drifting with the current are all there is to mark the grave of Sebb Jarel."
 * In Book 10 of the Lone Wolf series The Dungeons of Torgar, one of the paths to the end is to travel through the deadly Hellswamp with the partisan leader Sebb Jarel. Eventually, Lone Wolf and Jarel are ambushed by the dreaded Ciquali (frogmen) and Jarel is dragged underwater.

Literature

 * Macbeth's parallel of his wife's "Out Damned Spot" is the page quote.
 * The first Plague of Egypt in Exodus, when God turns the River Nile to blood.
 * The murder in the Lord Peter Wimsey novel Have His Carcase.
 * Warrior Cats has 's death, and to a lesser extent, 's death.
 * dies in a pond in A Series of Unfortunate Events books
 * A couple of times in Neverwhere, for example when Door's brother is killed and left in their swimming pool.
 * 's death is described that way in The Great Gatsby.

Live Action TV

 * In the first episode of the Melrose Place remake,  is found murdered in the pool of the apartment complex, with more than a little blood in the water around her.
 * In an opening to an episode of The Closer, there's a blink-and-you-miss-it shot of blood splashing into a swimming pool.
 * This trope is rather visible in the first season finale of The Sarah Connor Chronicles, when Cromartie disposes of an entire SWAT team into a swimming pool.
 * The fifth season opening of Supernatural.
 * Bathtub deaths form a major part of the Trinity Killer's pattern in Dexter.

Video Games

 * In Assassin's Creed, Altair's first target, Tamir, stabs a man to death and lets the body fall into a shallow pool of water which rapidly becomes red with blood.
 * The second time Jester pops up in Devil May Cry 3, he causes a nearby stone fountain (adorned with seemingly decorative gargoyles) to overflow with blood, awakening the now demonic Bloodgoyles to attack Dante, who isn't very intimidated.
 * In an old build of Dwarf Fortress, a single spattering of blood would turn an entire body of water red. Even the ocean.
 * It's still played straight; blood like any other contaminant lingers where it's washed off, and fills a tile of standing water or flows downstream with running water.
 * In World of Warcraft, if you kill a beast in the Borean Tundra, you find yourself covered with blood (which will piss off the local Animal Wrongs Group). You can wash it off by swimming in water, which will leave behind a "pool of blood." Repeatable fishing quests require you to do this deliberately because the blood attracts a unique type of fish.
 * Whenever the shark kills someone underwater in Jaws Unleashed during the cutscenes, it turns a big area in the water blood red.
 * The menu screen for Dead Island has this constantly going on as a background. It's actually quite pretty, rather like a lava lamp. Made of blood.

Music Videos

 * The swimming pool scene in Pink Floyd's The Wall.

Mythology and Religion

 * The Bible had the Nile turning to blood. While the blood wasn't from anyone dying, several movie versions have the blood fanning out from one source (usually Moses), giving off this effect as the transformation ensues.

Real Life

 * Truth in Television in that people who are sensitive to seeing blood will often do fine until they go to wash the wound and see the red spatters in the sink.
 * Similarly, cutting yourself in a swimming pool can be a harrowing experience.
 * Or having your gums bleed while brushing your teeth. Sink looks like a murder scene.
 * The worst is after getting your wisdom teeth removed, the holes will often bleed profusely, resulting in spitting huge mouthfuls of blood into the sink.
 * When doctors are treating people who have cut themselves badly and ask them to estimate how much blood they've lost, they take this trope into account, knowing that people who have bled into water are likely to grossly overestimate.
 * Not actually blood, but; Red Tide, a harmful algal bloom that turns water red and can kill fish and other sea-dwelling life.
 * When the carbon dioxide in Lake Nyos suddenly erupted from the water and killed nearly 1800 people, the disturbed iron turned the water's surface red.
 * Nicking yourself while shaving in the shower (more frequent for women than men) means that the blood takes much longer to clot than usual. "Ow! I'll need a bandaid" will rapidly become "jf;lkdsanvlkdan;ah WHY IS THE BATHTUB RED?!"