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"The Luminous Fish Effect" is the fourth episode of Season 1 of the American sitcom The Big Bang Theory. This episode first aired on Monday, October 22, 2007.


Sheldon is fired from his job and subsequently delves into numerous obsessions. Leonard decides that only one person can help Sheldon get back to his normal life: Sheldon's mother Mary Cooper.

Extended Plot[]

Mary and Sheldon 2

Getting Sheldon's job back.

Leonard and Sheldon are attending a party to meet the new physics department head, Eric Gablehauser. Sheldon is displeased with Gablehauser because he feels that he is unworthy. After telling him, he is swiftly fired.

Back in the apartment, Leonard is confident that Sheldon will get his job back if he apologizes to Gablehauser, but Sheldon refuses, as he explains this fact is his first day off in decades. He starts out by conducting experiments with scrambled eggs. Penny comes in and asks if Sheldon needs any groceries. As his demands for various types of eggs confuse her, Sheldon tags along. He manages to annoy her after lecturing her on the distance between cars, fun facts on tomatoes, multivitamins, and buying tampons in bulk. He also mentions her check engine light for the first time. Leonard comes back to find Sheldon experimenting with luminous (glow-in-the-dark) fish. He plans to market them as night lights. Next, he buys a weaving loom, making clothes, place mats, and other odds and ends.

Leonard brings Sheldon's mother; Mary Cooper to Pasadena to help with Sheldon, who was making serapes and ponchos. This action angers Sheldon and he runs to his bedroom. Mrs. Cooper remarks that Sheldon has her eyes, but the science stuff comes from Jesus. Later, Mary makes dinner for the gang, and explains that Sheldon was always like that. Refusing to eat dinner with them, Sheldon does come out of his room for some peach cobbler. Mary says that "you have to let Sheldon come to you". Leonard clearly ignores her warning and soon enough, Sheldon has locked himself in his room again.

The Luminous Fish Effect 3

Sheldon shopping with Penny.

The next day, Mary forces Sheldon to apologize to Gablehauser after reminding Sheldon of a similar thing that happened when he was younger. It was fine to be smarter than everyone else, you just can't keep talking about it. At Caltech, Mary introduces herself to Gablehauser and prods Sheldon to apologize. Sheldon swiftly gets his job back in a manner suggesting sexual barter between Gablehauser and Mrs. Cooper. The older couple seem to like each other. Finally, Sheldon asks his mother whether Gablehauser will become his new daddy. Mary answers cautiously, "We'll see". Sheldon then goes to sleep next to his newly engineered "Luminous Fish" night lights.



  • "A strangely written episode. The story is passable as are the jokes, but the focus is all wrong. The story should be about Sheldon’s place in the world and how he feels about it and yet we learn very little. The writers don’t seem to know what they were trying to achieve." - The TV Critic's Review
  • IMDb user reviews.


  • Title Reference: Sheldon produces glow-in-the-dark fish for use as nightlights in this episode.
  • Chuck Lorre's vanity card.
  • This episode was watched by 8.15 million people with a rating of 3.1 (adults 18–49).
  • Episode transcript.

Costume Notes[]




Unknown: Global?


Unknown: Bubble?


Gold Star

  • Sheldon wears a celestial graphic t-shirt, often called "Goodnight" at merchants like After being fired, he spends much of the rest of the show in a poncho or his pajamas and robe.  
  • Leonard wears a t-shirt with a graphic of a "Paradox Molecule" , a shirt featuring what looks like global satellite tracks, and an unidentified shirt resembling a bubble pattern.
  • Howard wears a gold star belt buckle.
  • Penny wears a Juicy Couture Terry Basic Puff Sleeve Hoodie in Sweet Grenadine, with Lucky Brand Orange Flower Shorts.

Set Notes[]

Superman 197

Superman #197


DC Special #17


Superman MOS #29

On the living room set, an aircraft vertical compass is seen on the island/stand to the left of the front door as Leonard enters. 

As this time is our first glimpse of Sheldon's room, EVERYTHING is "new" for viewers. The main items seen, in addition to Sheldon's bedroom furniture, from left to right, are:

  • Red lightning print framed to the left of the closet
  • Green and black photo or image framed to the left of the bedroom door
  • Wicker basket on the dresser
  • Media drawers on the dresser


  • First appearance of Mary Cooper.
  • First appearance of Dr. Gablehauser.
  • First appearance of Caltech.
  • First episode where Sheldon's brother is mentioned. His twin sister was first mentioned in the "Pilot".
  • This episode reveals that Sheldon's father is dead. He died long ago before the show started.
  • It is revealed that Sheldon started college right after finishing fifth grade.
  • Johnny Galecki and Sara Gilbert previously co-starred together in "Roseanne" (1988), which also featured Laurie Metcalf.
  • One of two episodes where Sheldon wears shorts; the other is "The Cruciferous Vegetable Amplification" (S4E2).
  • Sheldon weaving on the loom is mentioned again in "The Toast Derivation" (S4E17), where it is revealed that he made matching serapes for Leonard, Howard and Raj, the latter most of whom still wears it when the weather gets cold.
  • Sheldon's 'estimate' of 4,000 pounds for Penny's vehicle is grossly inaccurate. Modern midsize sedans average 3,200 pounds while her small Volkswagen Golf Cabriolet weighs closer to 1,900-2,100 pounds.
  • Sheldon claims Penny's car weighing in at 4000 pounds plus Penny weighing 120 and himself at 140 would equal a gross weight of 4400 pounds, when the correct math would be 4260 pounds.
  • Sheldon's mother mentions that he was born in a K-mart.
  • Sheldon's idea that he could simply invents a time machine in the future, go back in time, and give it to himself, thereby eliminating the need to invent it, is impossible as this fact is would be a Predestination paradox. A physicist like Sheldon should already understand it, as he points to such in "The Nerdvana Annihilation" (S1E14).
  • Penny misses the point of Sheldon's lecture on the 'dynamics of bacterial growth' when she says he should start heading out of the supermarket then, as Penny intends to drive Sheldon home when she is ready. (Counterpoint: Penny does understand the point Sheldon was making, Penny was simply trying to ignore him, or at least hint at him leaving for the duration of her shop because he was annoying her)
  • Sheldon's family name Cooper is revealed for the first time in this episode.
  • Inconsistencies
    • When Leonard, Howard, Raj and Penny are talking with Mary Cooper in the living room, a turned-on lamp can be seen through the open door of the bathroom - this lamp is more easily seen when Sheldon escapes from the living room; however, in the bathroom scene in the Pilot (when Leonard talks with Penny who is in the shower), there is no lamp on the wall opposite to the door. This time is probably because that the bathroom scene is filmed in a separated bathroom setting, while in the living room setting, the (supposed) bathroom door does not really open to the aforementioned bathroom setting.
    • Some time between Sheldon's mother ordering him to get dressed to go see Dr. Gablehauser, and Sheldon going to bed later that night, the comic books on the wall above the bed changed order. (Green Lantern is now on the right).
  • Genetically modified luminous fish aren't merely a thing of Sheldon's imagination. Genetically altered GloFish have been on the market since 2003. Fluorescent angel fish have been created, and were on display in Taiwan in July 2013. Cats have also been given florescent genes.
  • While talking about a death ray, Mary Cooper mentions a dog their family used to have when Sheldon was a child, which is inconsistent with both the Young Sheldon and The Big Bang Theory series, where dogs are mentioned. Sheldon is meant to be terrified of dogs.


Leonard: Howard brought a date?
Sheldon: A more plausible explanation is that his work in robotics has made an amazing leap forward.

Mary: (To Raj) I made chicken. I hope that isn't one of the animals ya'll people think is magic.

Howard: (With a woman) Hey, what up, science bitches?

Scene: Penny’s car

Penny: (she's being curious to Sheldon) How come you didn’t go into work today?
Sheldon: I’m taking a sabbatical, because I won’t kow-tow to mediocre minds.
Penny: (she grins sarcastically) So you got canned, huh?
Sheldon: Theoretical physicists do not get canned. But yeah.
Penny: Well, maybe it’s all for the best. You know I always say, when one door closes, another one opens.
Sheldon: No it doesn’t. Not unless the two doors are connected by relays, or there are motion sensors involved.
Penny: No, no, I meant…
Sheldon: Or the first door closing causes a change of air pressure that acts upon the second door.
Penny: (she grumbles for a bit) Never mind.
Sheldon: Slow down. Slow down, please slow down.
Penny: We’re fine.
Sheldon: Look, you’re not leaving yourself enough space between cars.
Penny: (she shouts crossly) Oh, sure I am.
Sheldon: No, no. Let me do the math for you, this car weighs let’s say 4,000lb, now add say 140 for me, 120 for you.
 Penny: (she's asking Sheldon crossly) 120?
Sheldon: Oh, I’m sorry, did I insult you? Is your body mass somehow tied into your self worth?
Penny: Well, yeah.
Sheldon: Interesting. Anyway, that gives us a total weight of, let’s say, 4,400lb.
Penny: (she's so very surprised) Let’s say 4,390.
Sheldon: Fine. We’re travelling forward at, good Lord, 51 miles an hour. Now let’s assume that your brakes are new and the callipers are aligned, still, by the time we come to a stop, we’ll be occupying the same space as that Buick in front of us, an impossibility that nature will quickly resolve into death, mutilation and… oh look, they built a new put-put course.

Scene: The supermarket.

Sheldon: This is great. Look at me, out in the real world of ordinary people, just living their ordinary, colourless, workaday lives.
Penny: Thank you.
Sheldon: No, thank you. And thank you, ordinary person. Hey, you want to hear an interesting thing about tomatoes?
Penny: Uh, no, no not really. Listen, didn’t you say you needed some eggs.
Sheldon: Uh, yes, but anyone who knows anything about the dynamics of bacterial growth knows to pick up their refrigerated foods on the way out of the supermarket.
Penny: Oh, okay, well maybe you should start heading on out then.
Sheldon: No, this is fun. Oh, the thing about tomatoes, and I think you’ll really enjoy this, is, they’re shelved with the vegetables, but they’re technically a fruit.
Penny: Interesting.
Sheldon: Isn’t it?
Penny: No, I mean what you find enjoyable.
Sheldon (as Penny selects vitamin supplements): Oh boy.
Penny: What now?
Sheldon: Well, there’s some value to taking a multivitamin, but the human body can only absorb so much, what you’re buying here are the ingredients for very expensive urine.
Penny: Well, maybe that’s what I was going for.
Sheldon: Well then you’ll want some manganese.

Scene: On the stairwell of the apartment building.

Sheldon: That was fun. Maybe tomorrow we can go to one of those big warehouse stores.
Penny: Oh, I don’t know Sheldon, it’s going to take me a while to recover from all the fun I had today.
Sheldon: Are you sure? There are a lot of advantages to buying in bulk. For example, I noticed that you purchase your tampons one month’s supply at a time.
Penny: What?
Sheldon: Well think about it, it’s a product that doesn’t spoil, and you’re going to be needing them for at least the next thirty years.
Penny: You want me to buy thirty years worth of tampons?
Sheldon: Well, thirty, thirty five, hey, when did your mother go into menopause?
Penny: Okay, I’m not talking about this with you.
Sheldon: Oh, Penny, this is a natural human process, and we’re talking about statistically significant savings. Now, if you assume 15 tampons per cycle and a 28 day cycle, are you fairly regular? (Penny shuts the door in his face.) Okay, no warehouse store, but we’re still on for putt-putt golf, right?

(Sheldon is sitting in his room, working on a genetic sculpture, when his mom walks in.)
Mary: Good Morning, Snickerdoodle!
Sheldon: Morning.
Mary: (Looking at Sheldon's sculpture) Aw, now that looks awful fancy - what is that?
Sheldon: It's my idea of what DNA would look like in a silicon based life-form.
Mary: But intelligently designed by a creator, right?
Sheldon: What do you want, Mom?
Mary: You know how your Daddy always used to say that you can only fish for so long before you've gotta throw a stick of dynamite in the water?
Sheldon: Yes.
Mary: (Picking out a shirt, pants, and shoes from Sheldon's closet) Well, I'm done fishing. You put those on.
Sheldon: What for?
Mary: Because you're gonna go down to your office, and you're gonna apologize to your boss, and get your job back.
Sheldon: No.
Mary: I'm sorry, did I start that sentence with the words, "If it pleases you your highness"?
Sheldon: I'm not going to apologize. I didn't say anything that wasn't true.
Mary: Now you listen here. I've been telling you since you were four years old, it's okay to be smarter than everybody else but you can't go around pointing it out.
Sheldon: And why not?
Mary: Because people don't like it! Remember all the ass-kickings you got from the neighbor kids? Now let's get cracking. Shower, shirt, shoes, and let's shove off. [Leaves]
Sheldon: Wouldn't have been any ass-kickings if that stupid Death-Ray had worked!

Sheldon: (Reluctantly apologizing to Dr. Gablehauser) We may have gotten off on the wrong foot when I called you an idiot. I was wrong... to point it out.

Sheldon: How’s this? Pleased to meet you, Dr. Gablehauser. How fortunate for you that the University has chosen to hire you, despite the fact that you've done no original research in 25 years, and instead have written a series of popular books that reduce the great concepts of science to a series of anecdotes, each one dumbed down to accommodate the duration of an average bowel movement. Mahalo.
Leonard: "Mahalo" is a nice touch.
Sheldon: You know, there are only eight consonants in the Hawaiian language.
Leonard: Interesting. You should lead with that.

Mary: Oh, you got yourself a loom. How nice.
Sheldon: Thank you.
Mary: Honey, why did you get a loom?
Sheldon: I was working with luminous fish, and I thought, "Hey...loom".