Why do mermaids wear seashells?

cause they like them

To sell movies.

Walt Disney's original Fantasia had girl centaurs with no bras, but that changed when he realized parents would not buy tickets to a flick that showed bare breasts, even on mythical beasts. 

Hula dancers didn't used to wear pants under those grass skirts, but the tourists straightened them out about that real fast.

Now this:
This post was edited by Not Sure at October 26, 2017 4:53 PM MDT

B shells are too small ...