As far as Disney Princess clothing choices go, function is rarely favored over fashion. With rare exceptions like Mulan, these gals are typically defined by stylish gowns and uncomfortable footwear, but no classic outfit has made audiences question as much as Ariel's.
The only accessory she opts for (aside from tools like the dingelhopper) is that stringy seashell top, and it's led to an amusing kind of thought experiment from fans. Why exactly does Ariel and the rest of the mermaids need that cover-up (besides the obvious reason that kids' movies don't often show nudity). It certainly didn't stop her from being active and saving Prince Eric, but it's still an interesting question.
Well, this video that's turned up online may just hold the answer, and it's probably not the one you'd expect.
Turns out, some fish will get airborne for some tasty, tasty nipple
I've heard friends say that fish have the tendency to go for nipples, but I've certainly never seen any video evidence to prove it.
That fish straight-up launches itself out of the water, aiming for that specific lure. Perhaps this is why the people of Atlantica take such precautions when it comes to this area of their bodies. You just can't trust fish these days, you know?