- Broken Base: The ending, for some. That the pace of the manga is rushed into the ending after Tsukimi comes back from Singapore is nearly undisputed, but the real base breaker is the "resolution" of the manga's romantic arc, and the Love Triangle between Shu, Tsukimi and Kuranosuke. In the ending, Kuranosuke and Shu are still in love with her, but decide to live together with the Amars with Tsukimi platonically and basically let fate decide if one day Tsukimi will choose one of them. This is bound to leave Kuranosuke/Tsukimi fans, who argue that the manga was essentially those two characters' relationship's journey, unsatisfied, and leaves the smaller Shu/Tsukimi camp hopeful, as Shu states that he hasn't given up on her, but ultimately with nothing to go on. Another camp just hates the lack of resolution itself. Of course, some people did like the ending, stating that it's not nonsensical for a manga that doesn't often go the traditional way to end like this (indeed, the narrator, presumably the mangaka herself, tells you to not pay much attention to it, as it is a 21st century princess tale, after all), that Princess Jellyfish was never that focused on the romance anyway, and that the ending manages to preserve the friendship between the three characters for a longer time (which is clearly Kuranosuke's way of thinking in the manga itself when suggesting that they all live together).
- Cargo Ship: Hanamori will do anything for his Benzs.
- Fan-Preferred Couple: In terms of the Sibling Triangle, fans like to ship Tsukimi with Kuranosuke because he likes her for the jellyfish otaku she is as opposed to Shuu, who can't even tell that "Before" and "After" Tsukimi are the same person. On the other hand, in the manga Shuu does eventually realize his mistake and barely makes anything of it. He continues to court her, also doing what he can to support her clothes-making efforts.
- Germans Love David Hasselhoff: While the manga is no slacker in its home country, it is very popular in the West. The author even comments on it in an omake, stating she was surprised with this popularity and with Princess Jellyfish being chosen as one of the 50 books for teens by the New York Public Library, as well as with the amount of cosplayers of the series in manga events overseas. Hilariously, her editor is also drawn in the same omake saying that he has no idea how this happened, as they didn't do anything in particular with this goal in mind.
- Hollywood Homely: Even in her frumpy clothes, Tsukimi is still pretty adorable. Which actually may be the point, anyway.
- Hollywood Pudgy: In addition to this. Most people probably wouldn't even realize Tsukimi is meant to be chubby if not for some offhand dialogue about how she can't fit into Kuranosuke's mother's clothes and the fact that she has to wear a size large for a dress from her own brand. You can only really tell in some of the colored pin-ups — most of the time she's just as cartoonishly skinny as everyone else.
- Ho Yay: Several male characters find Kuranosuke very attractive as Kurako, which isn't all surprising given that they don't know his true gender. Hanamori on the other hand, knows the secret and still mentions that he gets turned on by him sometimes, and that if Kuranosuke was a woman, he'd hit on him on spot.
- Memetic Mutation: AFROSEALED!
- Moral Event Horizon: Inari slipping Shuu a mickey, molesting him, and tricking him into thinking they slept together.
- The Scrappy:
- Many think that Mayaya and Bamba are annoying. Especially Mayaya with her constant overreactions and tendency to scream most of her dialogue. This goes mainly for the anime, where they're reduced to gag characters. In the manga, they get more time to help with the Jellyfish clothing line along with the other Amars, and Mayaya gets an expanded backstory.
- Inari, though again it does tend to depend on whether the fan in question has only watched the anime or continued on with the manga. For those who stopped with the series, she's often the most hated character in the show (see Moral Event Horizon for their reasoning). But for those who carried on with the manga, she's liked better or at least tolerated. It doesn't help that just as she was starting to get the tiniest bit of development beyond amoral Femme Fatale, the anime ended and cut it short. For some fans, the damage was done.
- Squick: Any scene with Kuranosuke's uncle, the PM, lusting after the cross-dressed Kuranosuke.
- Unfortunate Implications: There's only really one sexually active woman in the series and she's portrayed as villainous. Since she's the only incredibly sexual woman in the series, this unfortunately associates female sexuality with evil, while the virginal girls are "good". There's also how queerness tends to be played for laughs on occasion, both mentioned in this article.
- Unintentionally Unsympathetic: The Amars. We're meant to sympathize with them for not fitting into society, but the hostility they show towards pretty/fashionable women, even ones who are being nice to them, comes off as elitist.
- Unnecessary Makeover: Tsukimi is arguably a lot better-looking sans makeup and flashy clothes. The same argument could likely be applied to the rest of the Nuns as well.
- Values Dissonance:
- Kuranosuke's father not only brings Kuranosuke, the fruit of his affair, under the same roof as his wife; she also leaves home for some period of time when the lover and her son arrive, so nobody is uncomfortable.
- Also, Kuranosuke's mother despairs about being parted with her son, stating, that if he was a girl, he "could" live with her. Apparently, with Heir Club for Men she just has no say in this.
YMMV / Princess Jellyfish