How I Met Your Mother Wiki
How I Met Your Mother Wiki
For the actual Mermaid Theory as explained by Barney in this episode, see The Mermaid Theory (theory).
The Mermaid Theory

HIMYM episode 6x11 (123)

Himym 120310 640x480.jpg
First aired:
December 6, 2010
Pamela Fryman
Robia Rashid
Barney's Blog

Images (11)

Ted gets closer to Zoey and The Captain. Barney and Lily get in a fight, but Future Ted keeps forgetting what happened. Marshall and Robin spend time together.


Now that Zoey is hanging out with the gang, they are also seeing more of her husband, The Captain. However, they are all finding him rather creepy for some reason. That is, until Marshall bursts into Ted's apartment with an enlarged photo of him. He points out how the bottom half (smile) of The Captain's face is cheerful and the top half (eyes) "wants to murder you!"

Zoey calls and invites the gang to a retrospective for architect Frank Lloyd Wright. Nobody else wants to go so Ted says he will just go with Zoey alone. Lily cautions Ted that there are rules for a single guy to follow when hanging out with a married woman. Most importantly, he should never lie to the woman's spouse about anything.

Marshall explains how the rules change once married when it comes to friendships with members of the opposite sex. Robin adds that she and Marshall however can still hang out because they are old friends. Lily points out that the two actually never hang out so they agree to have dinner together. However, they soon realize that they are awkward alone because they don’t spend much time together outside of the group. Marshall explains that part of the reason they don't hang out is because of Barney's "Mermaid Theory." The theory states that no matter how much a man is repelled by a "manatee", as soon as they meet a clock starts ticking until the time when he will eventually see her as a lovely "mermaid." For example, after Marshall hired an unappealing female assistant, Iris, two years ago, Barney told Marshall that though he viewed her as a "manatee" then, as he spent more time with her, she would eventually become a "mermaid" in his eyes. Barney says the "mermaid clock" is starting to tick, and a little over a year later, his assistant does in fact seem like a mermaid to Marshall in his eyes, much to his horror. Marshall explains to Robin that he doesn't want her, as Lily's best friend, to turn into a mermaid.

The two return to Ted and Robin's apartment rather drunk where inebriated Marshall is horrified to find that Robin is gaining mermaid characteristics. However, she is able to stop the transformation when she throws up at his feet. After that, Marshall never worried about Robin turning into a mermaid again.

Meanwhile, Future Ted explains that Barney and Lily started fighting when Lily declined to hang out with Barney. Or was it because she called him a "big stupid octopus head"? Future Ted can't recall. He tries to explain how they started to make up when Lily saved Barney and his ice cream from being hit by a motorcycle but resumed fighting when Lily suggested Barney was fat, causing him to cry that one doesn't call a woman fat to her face. A woman? No, no, it must have been Barney who offended Lily. This seems to make sense until Barney performs a magic trick of causing a beer to float in front of her. Future Ted decides to give up telling this part of the story until he recalls that Barney told Marshall a mermaid would revert to a manatee if she became pregnant. Future Ted now recalls how the story really happened:

It was actually much later when Lily was several months pregnant. Lily declined to hang out with Barney because he always undresses her in his mind. Barney said she didn't have to worry because she was a manatee. Lily took offense. She started to forgive him when he rescued her and the unborn child from the motorcycle but got upset again when he suggested she was fat in the bar. He then caused a bottle of beer to "float" in front of her by placing it on her swollen belly. She was able to forgive him after he explained that she would be a mermaid again once her breasts swelled up to breast feed. She forgives him and Ted bursts into the bar in a dress exclaiming, "Now we're even!"

Back in the present, Ted and Zoey are out and he overhears her telling The Captain that she is out "with friends." Ted points out her lie and she assures him that she just doesn't want to worry The Captain who has a tendency to get jealous. This doesn't sit well with Ted and he goes to the gang for advice. Lily suggests that Ted spend time with both Zoey and The Captain so Ted decides to take them up on their offer to go for a ride on their boat.

When Ted arrives at the boat, The Captain tells him that it will be just the two of them. Ted believes that The Captain is going to kill him; this is underscored by various remarks from The Captain. With The Captain casually pointing out how isolated they are Ted decides he should let someone know where he is. Before he can, The Captain accidentally knocks his phone into the sea. The Captain says he has something for Ted so Ted decides to make a swim for it.

The Captain returns with a bottle of scotch and Ted starts to relax. However, it's right then that the boat hits a bump and Ted falls into the water. The Captain is able to rescue him and Ted admits that he thought The Captain was out to get him. The Captain explains that he was just hoping that he and Ted could be friends since he knows that Zoey likes him. Zoey confirms in the bar that this was the reason she absented herself from the boat trip. She and Ted agree that they shouldn't hang out if they have feelings for each other. They both deny any feelings, but a clock starts ticking, indicating that the mermaid clock has started.


  • Marshall's obsession with large printed graphics is explored in Right Place, Right Time.
  • Barney says Lily lies to Marshall when she says she loves his mom. Lily admitted her problems with Marshall's mom in The Stinsons.
  • When Barney mentions the "myth of the mermaid", Marshall sarcastically replies "I'm sorry, myth?" Marshall's belief in supernatural phenomena was first established in Matchmaker.
  • Barney claims that that the Mermaid Theory is a "thing", like how he tells the gang that the Lemon Law is "going to be a thing" in The Duel.
  • Future Ted previously had trouble recalling stories in How I Met Everyone Else and The Goat.
  • The Captain extended his invitation to Ted to join him on his boat when they first met in Natural History.

Future References (Contains Spoilers)

  • The Mermaid Clock ticking for Ted and Zoey foreshadows them getting together in Oh Honey​.
  • Marshall's theory about the Captain's creepiness is referenced in Garbage Island.
  • Ted's paranoia about the Captain trying to kill him resurfaces in Garbage Island and The Ashtray.
  • Ted walking into the bar in a green dress during Lily and Barney's fight is explained in Now We're Even​. It is also revealed in How Your Mother Met Me that the Mother and Louis were at MacLaren's that night.
  • Future Ted eventually remembers that Lily was heavily pregnant at the time of her and Barney's fight. She is indeed about eight months pregnant by Now We're Even, her and Marshall having conceived their child in August 2011, as revealed in Disaster Averted.


For a listing of all images on the wiki tagged as being from this episode, see Category:The Mermaid Theory images.

Memorable Quotes

Ted: Zoey just told me about this great Frank Lloyd Wright retrospective tonight, who's in?
Lily: Sorry, I'm... ah, I dunno, washing my hair.
Marshall: Running the water.
Robin: Holding the towel.
Barney: And I'll be home, trying to get over the fact that no one invited me to the big hairwashing party.

Ted: Uh, where's Zoey?
The Captain: Well, I'm afraid she's feeling a little under the weather. Looks like it's just you, me and six hours in frigid international waters.
Ted: Or we could stay on dry land, hang out with some witnesses.
The Captain: (laughs) You're a hoot. I've been looking forward to this. For a very long time. Well, anchors aweigh!
Future Ted: Kids, here's one thing I do remember. I was pretty sure I was going to die that night.

The Captain: What were those sailors thinking? Huh. I don't know. Being out at sea can do crazy things to a man. Vast, the sea. Deep. Endless. Going around for miles. You could scream and scream, and not a soul would hear you. Listen to this. (screams) Help! Somebody help me! I'm trapped on a boat with a madman! Help! See? Nothing. (laughing)

(both laughing)

(anxious laugh) He's gonna kill me.

Future Ted: Okay, back to Barney and Lily and whatever the hell they were fighting about.
Lily: Seriously? I step away for five seconds, and you eat all my onion rings? No surprise there.
Barney: What's that supposed to mean? Are you calling me fat? If there is one thing you never do, it is call a woman fat right to her face!
Future Ted: Wait. Barney's not a woman. That's right-- Barney wasn't hurt by Lily, Lily was hurt by Barney.
Lily: Want to hang?
Barney: Nah. (gasps)

Watch out! (gasps)

Lily: (panting) Wow thanks, Barney. You saved me. You saved us.
Lily: If there's one thing you never do, it's call a woman fat right to her face!
Future Ted: Okay, now I'm on track. The rest of this story should make perfect sense.
Barney: Oh, Lily, I'm sorry. Hey, you want to see a magic trick? (eerie whirring)
Lily: You're a jerk.
Future Ted: Okay, that makes no sense. Kids, I'm officially admitting defeat. I will never remember this story. I'm sorry for wasting your time.

Future Ted: Wait! That's it! That's what Barney and Lily were fighting about! The Mermaid Theory! But their argument didn't happen at the same time as all this other stuff. I'm literally in the wrong year! It happened much, much later when Lily was pregnant.
Barney: Well, Lily, I guess it's just you and me. You wanna hang? Nah. (gasps)
Lily: Whenever we're alone, you spend the whole time undressing me with your eyes. You even take off my shoes. High heels chafe my shoulders.
Barney: But you don't have to worry about that anymore. Ever since you got pregnant, you're just a big fat manatee. (gasps)
Lily: Well, you're a big stupid octopus face!
Future Ted: That was it! I remember now! Wow.
Lily: Thanks, Barney. You saved me. You saved us.

If there's one thing you never do, it's call a woman "fat" right to her face!

Barney: I'm sorry, Lily. Hey, you want to see a magic trick?
Lily: Oh You're a jerk.
Barney: (chuckles) Hey.

Notes and Trivia

Goofs and Errors

  • Marshall states that Robin and he have never hung out together alone. But in Little Minnesota​, they spend a few days alone at two different bars: Hoser Hut and Walleye Saloon. Also in Three Days of Snow​ they're seen to be going out alone while picking up Lily.
    • Later in the episode, Marshall tells Robin that he can't hang out with her "because of the Mermaid theory", which Barney explains him two years ago. Little Minnesota and Three Days of Snow​ was before that, so he might think that he and Robin never spent any time alone since.        
  • Before Robin turns back into a manatee, she throws up on the floor, but when Marshall leads her to the couch seconds later, the floor is clean.
  • The shadow of boat on The Captain's face disappears after a moment when he was talking to Ted at the shore.

Allusions and Outside References

  • Ted and Zoey attend a retrospective for architect, Frank Lloyd Wright.
  • Marshall and Robin give each other nicknames; Marsh Madness and Robocop.
  • Marshall suggests that Robin might start singing "Part of Your World" to his pants if she became a mermaid. This is a reference to Disney's 1989 film The Little Mermaid. "Part of Your World" is a song in the film.
  • Marshall states that the Captain "hates that he loves" the Jonas Brothers.
  • While Ted first comes onto Captain's boat, a green light can be seen in the distance, which is a reference to The Great Gatsby.
  • When discussing Ted's phone descending into the sea, he quotes "Can you hear me now?" referring to wireless phone provider Verizon's personification of a crew of employees who test the network; the "Can you hear me now? guy" appeared in many advertisements for the company starting in 2002.[1]
  • Barney parodies a line from Guns N' Roses song "Paradise City" saying "Manatee City. "Where the grass ain't green and the girls ain't pretty." The actual line is "Take me down to the Paradise City/Where the grass is green/And the girls are pretty."
  • Unlike most of Barney's historical explanations, the theory that sailors mistook manatees for mermaids is generally accepted as true.


Other Notes

  • Lily and Barney getting bored while Future Ted can't remember why they were fighting is the first time the characters break the fourth wall. 



Featuring an interview with Kyle MacLachlan.


  • This episode premiered to 9.255 million viewers.[2]
  • Donna Bowman at the A.V. Club gave the episode a B+.[3] She loved the running gag of Future Ted failing to remember the story properly, the opening gag with The Captain's large photo and the ending ticking scene with Ted and Zoey.
  • DeAnn Walker at Television Without Pity gave the episode a D-.[4] She felt that "This episode is totally confusing and makes very little sense at all. Not only that, but the "plots" that it "furthers" are tedious and full of plotholes."
  • Robert Canning at IGN gave the episode an 8 out of 10.[5] He praised Kyle MacLachlan's performance as The Captain. While not a big fan of Ted's storyline with Zoey this season, he felt the ending "tied the entire episode together nicely and helped make 'The Mermaid Theory' a memorable episode, despite being a part of this Zoey storyline." He also enjoyed the introduction of the mermaid theory, but notes that so many theories, rules and codes (such as The Bro Code, the Naked Man, and "Where's the poop?") have been introduced it may ruin these jokes in the future.
  • The St. Petersburg Comic Review gave this episode 7 out of 10 stars. "...Ted and Zoey are just, really...."


External Links

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False Positive