For some reason, mermaids feel compelled to fashion bras for themselves out of seashells, but they never care about making any other kinds of clothing. Although this provides Fan Service and Fetish Fuel, it was originally created for the reverse reason. Logically (as in, using the same logic that would apply to humans *cough*), a mermaid would be an Innocent Fanservice Girl, but we can't have that in a kids' movie, can we? Since, by definition, a mermaid is a fish from the waist down, it's only
Metal Gear, Tropedia
Lavender Seashell Bra, Gaia Items Wiki
Graceful Ladies Like Purple, Tropedia
Walking Swimsuit Scene, Tropedia
Adaptational Modesty - TV Tropes
Bare Your Midriff, Tropedia
The Legend of Zelda: A Link Between Worlds / Characters - TV Tropes
Fandom Heresy - TV Tropes
Sensible Heroes, Skimpy Villains - TV Tropes