The original Aquagirl (Tula) from Aquaman was a brunette in all of her comic appearances, from Aquaman to Teen Titans. She was changed to be a redhead in the Young Justice cartoon and Justice League: The Flashpoint Paradox (which used her Young Justice design as a nod to the cartoon). Her eyes were also changed from blue to green. Earlier on, the Teen Titans Go! comic book featured Tula in a brief cameo in issue 50 and a chibi gag. She was significantly changed up, with her brown hair becoming green, her eyes going from blue to gold, and receiving a sort of "Species Lift" from going from being a more humanoid Caucasian Atlantean girl to having pale blue skin, webbed hands and feet, and gills.
On that subject, Aqualad is almost always depicted with black hair, except in the Titans live-action series, where he's a blonde.
In Aquaman (2018), Patrick Wilson, who played Ocean Master, decided to bleach his hair to blond, ironically making Orm look like the classic Aquaman.
The DC Extended Universe did this to Aquaman himself, changing him from blond to Jason Momoa's dark looks with blond highlights.
Nora Allen from the Flash comics is blonde. She's played by dark-haired Spanish actress Maribel Verdú in The Flash.
Black Canary is traditionally naturally black haired. A part of her disguise was putting on a blonde wig, though in the 1990s she decided to just grow her hair out and dye it. The New 52 reboot originally had her as a natural blonde. Then they later retconned that and she's back to having naturally black hair. Birds of Prey (2020) splits the difference with Black Canary having dark hair with blonde highlights, although she’s played by Jurnee Smollett.
The eye colors of most main characters in Smallville are different. Lex Luthor has grey instead of green, Clark Kent has green instead of blue, Lana Lang has brown instead of green, Lois Lane has brown instead of blue/violet.
Has there ever been a live action Jimmy Olsen with red hair? Ever?
Dean Cain has brown eyes and brown hair; Tom Welling has green eyes (if fan sites are to be trusted) and brown hair; bothplayedSuperman, whose piercing blue eyes and black hair have been part of the standard character description for decades. At least Christopher Reeve was right.
Of course he had to get a real dye job to go from his natural blond...
The New 52 also bleached Freddy Freeman's hair. The movie has it black again, in something like the original style that Elvis Presley copied.
There was an Early Installment Character-Design Difference example for Beast Boy of Teen Titans fame. Back when he was in the Doom Patrol, in his original origin story he was shown to have brown hair. After 12 issues he was given blond hair and it's stayed that way. His hair became red in the cartoon Young Justice (2010). All of these are origin stories given little screen time compared to the green hair he is more well known for, which the color (whatever it is naturally) always changes to after his Superhero Origin. In the Titans (2018) live-action show, a Flashback shows that his hair was originally black before it became green.
Except in the New 52, where he turns red (blood-red, not red-hair-red), to fit better with the idea that characters with animal powers are all linked to The Red and characters with plant powers to The Green.
In the New 52 reboot, Terra originally appeared with (and was intended by the artists to have) brown hair, as opposed to her classic blonde. Later colorists have changed her hair back to being blonde, probably to have her look more recognizable.
While Raven has black hair in the comics, the 2003 animated series depicted her with violet hair. Her mother Arella received a similar dye job. Raven's eyes were also depicted as blue in the comics up until her resurrection, where they officially became "indigo" and vacillated between being a deep blue or violet. The animated incarnations of Raven and Arella both sport violet eyes. In the Teen Titans Go! cartoon, Raven's hair becomes a much deeper violet, almost black.
Kole Weathers was a redhead in her short-lived comics existence, while her animated counterpart had bright pink hair.
Three fourths of the Titans from the Elseworld "Scissors Paper Stone" undergo this in the New Teen Titans short "Turn Back The Clock", as Captain Thug went from having red hair to magenta, and both Dead Pretty Boy and Witchie-Poo were changed from having black hair and brown hair respectively to red hair. Prosthetic Lass is the only one who still retains her hair color from the original comic (blonde).
The Wonder Woman of the main universe has black hair, however several of her alternate universe counterparts are red-heads (The unnamed pirate Wonder Woman of Earth-31 and War-Woman of Earth-36), blonde (Brünhilde of Earth-10), purple haired (Vague of Earth-41) and strawberry blonde (Walküre of Earth-7).
The Superman of the main universe has black hair, however several of his alternate universe counterparts are blond (Hyperius of Earth-8, Savior of Earth-34 and Optiman of Earth-36), green haired (Super-Martian of Earth-31), white haired (Supremo of Earth-35) and strawberry blond (Cyclotron of Earth-39).
The Catwoman of the main universe has black hair, however her Earth-31 counterpart has purple hair.
Hoppy the Marvel Bunny, Shazam!'s Funny Animal counterpart, was originally pink-furred, as were other bunny residents of Funny Animalville. When he was introduced to the Bronze Age DCU, he was white. In the Post-Crisis DCU he was shown as pinkish-brown on the cover of The Power of Shazam #29 and white with pink highlights inside. In Tiny Titans and DC Superpets he's brown and white. And the unpowered, non-anthro Hoppy from The New 52Justice League's Shazam back-up strip is white again.
Variation in Superman: Red Son in the comic Supes’s gets grey temples as he ages. In the animated film, his hair stays black as The Ageless. In the same movie Superior Man has normal Caucasian colored skin instead of sickly pale like in the comic (though he soon has Superpower Meltdown and gets the pale complexion) whilst Jimmy Olsen is black in the animated film.
Sort of inverted, originally a pre-Beast Boy Garfield Logan was show to be brown-haired but was subsequently retconned as a blond a few issues later and remained so ever since. Here he is brown-haired once again before his powers activate.
In the main universe Rita Farr is a brunette, Rita Markov here has black hair.
Beast Boy has a completely different hairstyle then he did in Teen Titans. It resembles his contemporary comic book hair more.
Blackfire is much paler than in the 2003 cartoon.
Starfire has hot pink hair rather than the usual red hair she sported in the original animated series and DC Nation spin-off shorts.
Raven has black hair instead of purple, and the hairdo is also different. Ironically, aside from Robin, this makes her look more faithful to her comic book counterpart.
Speaking of which, Barry's hair is black in the live-action Justice League movie.
Kara Zor-El aka Supergirl who appears in The Flash (2023) is played rocking Sasha Calle with short dark hair rather than the traditional blonde and long hair. This was intentionally done to match her up with the rest her family as there’s a Bait-and-Switch making you think it’s a Clark before she turns around and says her name. Ironically a prequel comic to Man of Steel had the classic blonde version of Kara.
The Suicide Squad: Ratcatcher's hair is usually blond or reddish brown in the comics, in the film’s grey haired and his daughter/successor is dark haired.
Superman: Brainiac Attacks: Mercy Graves is a blonde in the movie whereas she was a brunette in the series.
Live-Action TV
Felicity Smoak has black hair in the Firestorm comics, but is played by a blonde actress in Arrow. This is later revealed to be a literal example, as flashbacks show Felicity with black hair, and it has been stated a few times that she dyes it blonde.
Barry Allen, a blue-eyed blonde, is played by brown-haired, green-eyed Grant Gustin. He was also played by the dark haired John Wesley Shipp on the 90's Flash series. The 90s show also had Tina McGee go from black hair to brown.
Jesse Quick is a blonde in the comics, but has auburn hair in the show.
Subverted with Eobard Thawne; he had dark hair when disguised as Harrison Wells, but it's established in a flashback that he's blond like his comic counterpart.
Savitar has jet-black hair with blue streaks in the comics, but the show gives him brown hair. His comic counterpart also produced white lightning as he ran, but this version has yellow lightning that only looks white because of his Powered Armor.
Iris and Wally West both have black hair instead of red (due to the fact they are not white characters in the TV series).
In Neil Gaiman's Lucifer the abdicated Lord of Hell is blond, but in the loose TV adaptation he has black hair. It gets referenced in one episode where a Satanist responds to Lucifer's assertion of being the Devil by saying, "Aren't you supposed to be blond?"
Death is famously a Eerie Pale-Skinned Brunette in the comics, but in the show she’s played by black actress Kirby Howell-Baptiste. As noted by Gaiman himself, Death can appear in any form she wants so skin color is irrelevant.
Just to show the aforementioned 2005 movie isn’t only the media to do this to John Constantine, the series also makes Constantine dark-haired as well as a woman thanks to being played by Jenna Coleman. Though according to Neil Gaiman she’s meant to be a seperate character from Alan Moore’s Constantine with only the surname and demon expelling being the same.
Dream himself has completely white skin and black eyes with points of white in the comic. In the show he’s got slightly pale Caucasian-coloured skin and normal eyes (apart from a brief moment in the first episode). According to Gaiman again, this was changed due to the effect not coming out right. Dream’s coat also has a awesome burning red and orange effect look in the comics, in the show it’s all black likely for budgetary reasons.
Rose and Lyta have blonde and white hair in the comic respectively, in the show Rose has dark hair thanks to a Race Lift and Lyta also has black hair.
Calliope is blonde in the comics, but is dark haired in the show, which does in some ways fit her Greek ancestry better.
In a break from fairer hair getting turned dark, Desire is changed from dark hair like the comic to blonde in the show.
Despair much like Dream has her skin colour changed from “vampire” to Caucasian and her hair is brown rather than black.
Supergirl is usually a bright blonde. In the series her hair is so dark that it could pass for light brown.
In the comics Streaky is a ginger cat. In the Supergirl episode "Legion of Super-Heroes" he's played by a black cat.
Brainiac 5's natural form has white hair and blue skin, rather than blond hair and green skin. Presumably, this is partly to make him look distinct from the Martians, and partly because the first Coluan to appear on the show was the blue-skinned Indigo. Season 5 reveals that his natural form is indeed a green-skinned blond, and the colour shift is a side-effect of a self-imposed Restraining Bolt.
Sylvester Pemberton had black hair in the comics, but blond hair in the Stargirl (2020) TV show.
Web Animation
Lobo (Webseries): Darlene Spritzer is a redhead in the comics. In this cartoon, she is a blonde.
Batgirl in the Shea Fontana series wears a dark blue suit, while in the Lego projects, she wears purple. In the Lauren Faust series, she keeps the purple suit, but now has green eyes instead of blue.
Zatanna normally has black hair, but in this series, she has purple hair.
The Jim Harper Guardian is portrayed as a blond in the comics, but is given red hair in Young Justice (2010) in order to highlight his relation to Roy Harper.
Static villain Hotstreak went from having blond hair to red hair with blond streaks in Static Shock.
In the Superman/Aquaman Hour of Adventure, Wally West had black hair rather than red, with his Kid Flash uniform colored red instead of yellow. The Green Lantern segments also gave the Guardians of the Universe a generic caucasian skin tone instead of giving them blue skin like in the comics.
Due in part to the Race Lift he receives for this show, Jimmy Olsen is depicted with black hair rather than his traditional red hair.
Livewire, in both the comics and the previous Superman cartoon that she originates from, is depicted as having black hair prior to getting her powers and with blue hair after. Here, she has platinum blonde hair.
Silver Banshee in the comics has white hair with streaks of black, while in this show, she has bluish gray hair.
In the comics, Steve Lombard is commonly portrayed as having either red or brown hair, while in this show, he has black hair.
Vicki Vale is usually depicted with either red or blonde hair in the comics, whereas here, she has black hair.
