The Hero and the Romantic False Lead have one goal in common: getting the girl. In essence, a Cock Fight is what happens when the vying between the two suitors escalates into open hostility. Often occurs if neither was aware of the existence of the other, or when the hero has been courting the girl for a while. Typically, the fighters tend to focus on each other with the woman becoming secondary goal or, in a nastier tone, treated as a trophy.
As the title implies, this trope is Always Male and is very different from a Betty and Veronica situation in its execution. Namely, it is more about posturing and machismo and much less about emotions; it tends to be more violent and physical, instead of being catty and verbal.
Needless to say, this is a staple of romantic films, however, it can show up in any type of work. Usually, this happens before the girl's heart is clearly settled between her two suitors but, even when her choice is made and spoken out, there is still a chance for the Cock Fight to turn up again, since Romantic False Leads are not known for giving up easily. If the Romantic False Lead utterly refuses to acknowledge defeat, the next step is almost always If I Can't Have You.
When it comes to the competition itself, it is generally about displaying protectiveness, doing nice things for the girl, strength contests and other kinds of...er...symbolic measurements comparisons, preferably in front of her. More often than not, things can get out of hand — sometimes up to physical confrontation — if one of the suitors gets too close to the girl in front of his rival, or worse still, if he openly claims the girl for himself.
During such conflicts, the girl can either stay neutral or try to intervene whether or not her choice is made. If she takes the second option, what she does can go from trying to soothe the guys's differences, telling them to shut up and stop fighting over her, or even get the HELL out at least until they stop being stupid.
This is a subtrope of the Love Triangle and related to Triang Relations. Highly probable in a Two Guys and a Girl setting. Often happens after a Green-Eyed Epiphany.
Contrast Courtly Love, If I Can't Have You, and Stalker with a Crush. See also Opposites Attract Revenge for what this might lead to.
Not related to Cat Fight, but if two girls have mutual interest over the same dude, they can get into one. Very rarely overlaps with a Dogfight, however (Ace Pilots are too classy for that).
This trope is named for the rooster as a metaphor for a male animal which fights over a mate...though the double-meaning is not unintended. For literal animal fights, see Beastly Bloodsports and Mon. It has nothing at all to do with the word's secondary meaning of "the penis".
Tristan/Honda vs. Duke/Otogi in Yu-Gi-Oh!, over Serenity/Shizuka.
An odd and incredibly tragic variation in Berserk. The first time Guts and Griffith fought was not (directly) over Casca, but it did mark a turning point as her affections and loyalty shifted from (defeated) Griffith to (victor) Guts. Neither had openly displayed romantic or sexual feelings toward her up to that point. Later, after Guts and Casca had become a couple, Guts and Griffith "fight" again. It's less a fight and more of a Curb-Stomp Battle as Griffith forces Guts to watch as he rapes his lover Casca. The implication is that it's far more about hurting and humiliating Guts than about any attraction for Casca herself.
Narrowly averted in Junjou Romantica. Akihiko was about ready to storm in his brother's room and give him a good punch in every imaginable part of his body when he found out that his brother was 'going to take Misaki from him', had Misaki not held him from going through the door.
This is a subplot of Hayato and Randoll's rivalry in the latter half of the Future GPX Cyber Formula TV series as they competed for Asuka's love in the Spanish GP, and at one point, Randoll even made a bet with Asuka that if he wins that race, he gets her kiss (that never came to be).
And in the Suzaku hi den novel/OAV's, Hotohori again finds himself in a similar predicament when both he and his half-brother Shu show interest in Houki. It ends in tragedy: Houki chooses Hotohori, but Shu ends up dying in the arms of both of them.
Ash's Oshawott and Dawn's Piplup over Meloetta, during the Dawn arc of Pokémon 'Best Wishes'.
A Phione tried to challenge Ash's Pikachu to a fight over Dawn's Buneary, only for Buneary herself to defeat the Phione. Pikachu was confused about the whole thing.
In the main continuity, both still fight and squabble regularly over Jean as well.
In Excalibur, Nightcrawler got in a very violent fight with Captain Britain over Meggan. Captain Britain thought he was invoking this trope, but in reality, courtesy of grinding stress, a bout of alchoholism, a curse, and exceptionally poor phrasing on Nightcrawler's part, he overreacted and took a swing at his teammate. Nightcrawler, for his part, was strongly tempted by Meggan, but steadfastly refused to act on it in any fashion.
Cutter vs. Rayek vying to woo Leetah in the ElfQuest Trial of Head, Hand and Heart arc. Slightly subverted in that whoever wins, Leetah has the final say. Then re-subverted in that she's Recognized Cutter and ultimately can't fight it.
Putting Donald Duck, Gladstone Gander, and Daisy Duck in the same story is a recipe for disaster... and humor. It's interesting to note that in Daisy's eyes she is "officially" engaged to Donald, and the boys' attempts to impress her romantically either go unnoticed or frustrate her to no end. These stories also tend to play up Donald's bad luck and contrast it with Gladstone's legendary good luck, such that the former is desperately afraid of losing his girl while the latter is desperately trying to win the one thing his luck can't provide. Jealousy, envy, and wacky hijinks all around.
Films — Animation
In The Rescuers Down Under, Bernard competes with Jake over Bianca's affections. Though in this case, Jake isn't openly competing with Bernard, just unaware of his relationship status with Bianca.
Bambi and Faline's dance of love through the clouds is rudely interrupted by another stag, resulting in a savage fight.
In the "Baia" segment of The Three Caballeros, several men (including Donald Duck and Jose Carioca) vie for the affections of singer Aurora Miranda(Carmen's sister). At one point, two men stage a stylized dance-fight, with the animation morphing them briefly into roosters.
Films — Live-Action
In The Green Hornet, Britt Reid and Kato's argument turns violent after Kato implies he's been with Lenore Case (though it's revealed later that he was more concerned with antagonizing Britt). Despite Kato's Crazy Awesome credentials, it's not the fight you'd expect, especially when it ends.
(two naked men in a pitch-black bedroom are both wearing glow-in-the-dark condoms, and discover they're both trying to have sex with the same woman. All we see are two erect phalluses moving around the room. At first, the two of them are throwing stuff at each other, then, they get interested and start swinging their [glow in the dark] dicks at each other) (scene change) Man in Bed Answering phone: Uh, Hello? Yeah? Oh really. Okay, I'll come down and bail you out. (hangs up) Wife: What happened? Man: Jack's been arrested. Wife: What's the charge? Man: Cockfighting.
Andy and Dwight of The Office (US) "duel" over Angela (That is, Andy pins Dwight to a hedge with his car while his back is turned). In a later episode, when characters are musing over bad past breakups;
Angela: My worst breakup was actually two breakups. Two different men. I was in love with both of them and, when things went bad... they had a duel over me. Oscar: Yeah, Dwight and Andy, we were here. Angela: No. This was years ago when I was living in Ohio. John Mark and John David. Oscar: Angela... you had two sets of different men actually duel over you? Angela: I guess I have...
Inverted in The Next Karate Kid. Ned gets jealous of Julie and Eric hanging out and challenges Eric to a fight.
This Means War is about two CIA agents and Fire-Forged Friends, Tuck and FDR, using all of the resources at their disposal trying win over Lauren, a woman they both happened to meet on the same night. The fact that there is a very dangerous international terrorist seeking revenge on them for the death of his brother is actually a distant secondary plotline in comparison for most of the movie.
Discussed for tragic irony in Irreversible; near the end of the film (which, due to the reverse chronology, happens before the other main events,) Alex's boyfriend playfully says that he "stole" her from a friend of his (with whom they both remain on good terms nonetheless,) to which she says that he can't "steal" her because it's always the woman's choice and "(she is) not an object". This comes after the audience has watched her being used as exactly that and having her choice violated in the most brutal way possible during the film's notorious eight-minute rape scene.
Live Action TV
One episode of Angel had Wes and Gunn get into a physical fight because they were both in love with Fred.
Angel and Riley essentially do this on Buffy the Vampire Slayer in one ep as well. Buffy threatened to hospitalize them if they kept it up.
Angel and Spike do this over Buffy, just adding one more aspect to their competitive relationship. In Buffy's "Chosen" they both show their petulant jealous sides, but Buffy is more amused than angry. She eventually tells Spike that one day she's just going to put the two of them in a room and let them wrestle it out. When Spike says that's fine with him, her eyes widen in excitement and she says "There could be oil of some kind involved..."
That '70s Show: Hyde and Kelso once spent an episode fighting for Jackie's attention. When they get fed up with her jerking them around and tell her to choose, she says she can't. Then she chooses herself.
How I Met Your Mother: While Robin's dating Don, Barney decides he wants her back, leading Ted to the same revelation. They both get blindingly drunk and beat the crap out of each other, then try to drag Don into a three-way cock fight. He declines, because, unlike them, he's sober. And since she's with Don, they both lose. In the long run, Barney wins.
In Malcolm in the Middle, Hal and Lois each set their babysitter up with, respectively, Abe and Craig, and she tries to date them both simultaneously until it leads to this. The two guys being who they are, though, it's just a furious slap fight, and she chooses to dump both of them and "concentrate on her career" (despite having managed to lose the baby in all the excitement).
In The Vampire Diaries, Stefan and Damon over the affections of first Katherine and then Elena.
Richard Castle and Beckett's ex-boyfriend Will Sorensen. Halfway through the episode, Beckett flat-out suggests they just drop their pants and get it over with.
Parodied in an episode of The Big Bang Theory; when the gang can't agree who gets to ask out Sheldon's sister Missy, they decide to fight over her "the right way -- the honourable way"... Wii Boxing. Leonard wins, triumphantly walks over to her door and asks her out... and she flatly turns him down. Leonard muses that that was an outcome they hadn't anticipated.
Variation in Fried Green Tomatoes: In the book, Ruth's husband fights with Ruth's lesbian lover, Imogen (Idgie), when Ruth says she wants to escape her abusive marriage to live with her.
Colas Breugnon has the protagonist reminiscencing on his young love, which eventually drove him to fight his friend Pinon for her affections, to the death (but nobody died, though there was a lot of bleeding). Both competitors are even referred to as roosters.
In Our Mutual Friend by Charles Dickens, a rivalry of this nature springs up between upper-class lawyer Eugene Wrayburn and schoolteacher Bradley Headstone, over Lizzie Hexam. Particularly in Headstone's case, it's debatable whether love for Lizzie or hatred for the other man is stronger.
In A Song of Ice and Fire there was a non-heroic example of this long before the events of the book. Though she eventually married Eddard Stark, as a child Catelyn was betrothed to his older brother Brandon (who died in an unrelated incident) but was loved by a young Petyr Baelish (who would grow up to become the series premiere Magnificent Bastard Littlefinger). This rivalry over Catelyn eventually led Petyr to challenge Brandon to a duel for Catelyn, where he got utterly curb stomped. The resulting effect on his character causes no end of problems for the whole of Westeros.
Also in the back story is the cock fight to end all cock fights. Robert was rather understandably furious when Rhaegar kidnapped/eloped with Lyanna, his betrothed, which then sparked a war. When Rhaegar and Robert finally met at the end of said war, they had an epic battle that Rhaegar fatally lost. Unfortunately for pretty much everyone, Lyanna died anyway.
Amelia Peabody finds watching her husband Emerson fight the 'Master Criminal' Sethos for her quite an 'interesting and stimulating sensation.
What makes two people who are friends and comrades in battle fall apart? Being mutual lovers of the same girl. This is the fate of Akihiko Sanada and Ken Amada in Persona 3 Portable. Granted it's only relevant in Tartarus and is optional but oh, those wars. (And Ken is surprisingly able to hold his own, despite being younger than the standart.)
An ongoing character arc between Gilgamesh Wulfenbach and Tarvek Sturmvoraus in Girl Genius, both vying for the affections of Agatha Heterodyne and neither holding the other's integrity of character in particularly high regard. Played with at least a couple of times where Agatha has shown herself to be willing and capable of stepping in and kicking both of their asses just to get them to behave for a while. Of course, given that they are Vitriolic Best Budsand each other's political rivals, they do surprisingly little fighting over Agatha. After all they don't mind Agatha being the boss of them.
Sarine: Oh, hello, Jon. We were just having a little girl talk. Sweaty, violent, mostly one-sided girl talk with lots of sword fighting. Jon: ... Ah. Now see, guys don't have those kinds of talks. We just whip it out and see whose is longer.
In The Dreamer, Alan Warren and Alexander Hamilton often get into snippy fights around each other, often involving Beatrice as the subject.
Homestuck had a bizarre instance of this resulting from culture clash. In short: Karkat thinks Dave is dating Terezi, which Dave denies. Karkat also wants to date Terezi, and suggests an unnecessarily complicated form of polyamory as a solution. Dave is mortified that they're even having this conversation. Fisticuffs ensue when Karkat tries to draw a diagram of his plan, the boys spend several pages squabbling over a pen, Dave forces Karkat to draw several penises with said pen, and Karkat tells Dave to stop flirting with him.
This is the premise of nearly every Popeye cartoon ever made, ever.
In Tom and Jerry, Tom and Butch are often in competition over the affection of an attractive female cat.
Ulrich and William over Yumi in Code Lyoko. Actually came to blows in "A Bad Turn"... and that's just the beginning!