Japanese Title: Hanada Gym! Underwater Battle!
Original Airdate: September 3rd, 1998
US Airdate: September 23rd, 1999
At least James isn't wearing the Fake Boobs this time.
The one where... Misty dresses up as a mermaid.
One of Misty's water Pokémon is in desperate need of exercise, so the gang decides to take her Horsea to a gym that's run by her sisters in Cerulean City. But, Misty gets more than she bargains for when she learns that her sisters are planning an exciting underwater ballet—and they want her to be the star!
This episode contains examples of the following tropes:
- Acrophobic Bird: Our heroes find out for the first time that Psyduck can't swim. Misty's sisters even lampshade how incompetent he is.Daisy: Her Psyduck is embarrassing.
Violet: Like totally! - All Part of the Show: The crowd believe this regarding the Team Rocket interference.
- Artistic License – Physics: Dexter is somehow able to work underwater.
- Ballet Episode: An underwater synchronized swimming show is the centerpiece of this episode. Driven home by the disguises Team Rocket chose for the episode's heist.
- Banging for Help: Violet and Lily do this after being bound, gagged, and stuffed in a closet by Team Rocket, who wanted to take their place in the play that was happening.
- Bathtub Mermaid: Misty can't raise her Horsea properly because she can't find any large bodies of water to let it get some proper exercise, so she heads back to the Cerulean Gym to use the large swimming pool.
- Bound and Gagged: Daisy discovers Violet and Lily stuffed in a closet with their hands tied and their mouths gagged after Team Rocket stole their places.
- Cross-Cast Role: In-universe, Daisy casts herself as a "Prince" in the ballet.
- Damsel in Distress: The Magical Mermaid is supposed to be captured by pirates who interrogate her for the hidden treasure, only to be then rescued by the Prince. However, due to Team Rocket's intrusion in the plot, it's the Water-type Pokémon that become the damsel in question, with Misty breaking out of character to save them alongside Ash and Brock.
- Early-Installment Weirdness: The Cerulean gym has actual fish in the tank, rather than Water-type Pokémon.
- Incestuous Casting: In-universe; Daisy and Misty are sisters, but their characters are love interests.
- Long Hair Is Feminine: Misty has a short Tomboyish Ponytail, matching her fiery personality, but the Magical Mermaid she's supposed to play is a traditional sweet, girly princess. So she wears hair extension as part of her costume to look graceful and serene in the ballet. Of course, it ends up being subverted when Team Rocket interferes, which forces Misty to go out of character and resume her tomboyish attitude... while still wearing the mermaid hair extension.
- Mermaiding Swimsuit: Misty is playing the role as The Magical Mermaid, and she wears a mermaid costume throughout most of the episode.
- Ms. Fanservice: Misty when she is dressed up as the Magical Mermaid.
- Mythology Gag: Misty literally lives up to her game counterpart's title as the "Tomboyish Mermaid" here; a graceful and lovely mermaid when performing a show who quickly switches back to her fiery determination upon seeing Team Rocket, a far-cry from the role her sisters want her to play.
- Not Drawn to Scale: Arbok is absolutely humongous in this episode compared to how it's normally drawn.
- Out-of-Character Moment: "And next time, we steal men's clothes." This was said by James, most famous for cross-dressing with no shame.
- Put on a Bus: Horsea is left at Cerulean Gym for health reasons, and then Misty is convinced to give her sisters Starmie as well. They beg for her to leave Togepi and for Ash to leave Pikachu, but they refuse. She tries leaving Psyduck as well, but her sisters won't have it.
- Real Men Wear Pink: James mentions having studied ballet when he was younger.
- Seashell Bra: Misty wears one when she performs as the Magical Mermaid, though the material is most likely made out of fabric as opposed to actual shells.
- Shout-Out: The title is one to The Little Mermaid, with Misty even wearing a mermaid outfit not too dissimilar to Ariel's.
- Strong as They Need to Be: Jessie's Arbok is often knocked out in one or two hits, yet despite being outnumbered 4 to 1 against Squirtle, Seaking, Horsea and Starmie (Weezing not fighting as explained above) manages to hold its own and has the advantage until Seel evolves into Dewgong.
- Super Not-Drowning Skills: For some reason, Misty suffers no ill effects from opening her mouth underwater. For that matter, nor does Arbok.
- Took a Level in Badass: Seel (presented as completely useless during Ash's first visit to the gym) evolves into Dewgong and wipes out Team Rocket. This is discussed by Misty's sisters, who admitted they never actually let it battle.
- Travelling at the Speed of Plot: From Viridian to Cerulean City, considering the number of episodes that the heroes took travelling between the two cities before.
- Weaksauce Weakness: Weezing, a living gas bag, proves to be useless in an underwater battle.
