- Awesome, Dear Boy: Octavia Spencer jumped at the chance to work with Guillermo Del Toro - saying she "would have played a desk" if he'd asked.
- California Doubling: The movie's fictionalized Baltimore was shot in Hamilton and Toronto.
- Creator's Favorite Episode: Del Toro has said that this is the film he's most proud of. And that he would have retired from directing if it had flopped.
- Divorced Installment: The idea started as a remake of Creature from the Black Lagoon more sympathetic to Gill Man, but Universal wouldn't let it happen, likely due to their still having big plans for the Dark Universe at the time.
- Doing It for the Art: Del Toro self-financed the team that designed the creature and the lab.
- Fake American:
- Due to being filmed in Ontario, many of the extras are Canadian. This is even joked about in a scene where Montreal-born Morgan Kelly's pie shop counterman drops his thick Texan accent and confesses that he's from Ottawa.
- Sally Hawkins is a downplayed example. She's British playing the presumably American girl Elisa. But as she's a mute who never speaks, she doesn't have to fake an accent.
- Fake Russian:
- Michael Stuhlbarg (American) plays Dimitri who is Russian but speaks with an American accent presumably as part of his cover.
- Nigel Bennett (British) as Mihalkov.
- Fan Nickname: Grinding Nemo, due to a highly touted sex scene between Elisa and the Asset.
- Inspiration for the Work: The film was primarily inspired by del Toro's childhood memories of seeing Creature from the Black Lagoon and wanting to see the Gill-man and Kay Lawrence succeed in their romance.
- Irony as She Is Cast:
- Nick Searcy, the actor who plays General Hoyt, holds the same beliefs espoused by Strickland, which are potrayed in a negative light in this film.
- David Hewlett, who played a Hot-Blooded Hate Sink in Rise of the Planet of the Apes, another sci-fi by 20th Century Fox, is a security head who is a meek Yes-Man being bossed around by this film's own Hate Sink.
- Missing Trailer Scene: A split-second scene from the trailer missing in the final product has Strickland murdering Fleming. In the context of the movie, presumably for not getting out of his own car. This may explain why the civilian police arrive in force in the film's final moments, too quickly for it to be in response to the gunshots.
- Production Nickname: The Asset was nicknamed "Charlie", as in food mascot Charlie the Tuna.
- Self-Adaptation: The novelization of the film was co-written by del Toro.
- Shrug of God: Del Toro won't elaborate on what the Asset's sexual organ looks like beyond saying that a fanmade prop isn't accurate.
- Throw It In!: In the scene where Strickland arrives at Elisa's flat, Michael Shannon lost control of the car and drove it up onto the sidewalk and into a telegraph pole. Del Toro kept the take as it fit Strickland's increasingly unhinged and desperate mental state.
- What Could Have Been:
- Del Toro briefly considered shooting the film in black and white.
- The character of Giles was written with Ian McKellen in mind for the role.
- Word of God: Del Toro wrote lengthy backstories for each of the characters, though he told the actors they didn't have to take them on. Richard Jenkins ignored the one for his character, but Michael Stuhlbarg followed his closely.
- Write What You Know: Director Guillermo del Toro stated that the film is meant to reflect on how he feels to be living in America as an immigrant; all of the sympathetic major characters are outsiders in some way, and more or less isolated.
Trivia / The Shape of Water