American Title: "The Misty Mermaid".
Since Ash registered Dewgong underwater, the Pokédex is apparently waterproof. This also marks the first time Ash uses the Pokédex underwater.
Unlike its pre-evolution Ekans, Jessie's Arbok is shown to have the ability to breathe underwater. James's Weezing, however, is less dense than water and immediately floats to the surface.
Misty's Horsea is revealed to know Smokescreen.
In the final exchange of the dub, Ash compliments Misty's performance while Misty tells him flattery won't make her forget about her destroyed bike. In the original, Ash reaffirms his original suspicion of the Gym while Misty tells him not to think much of it.