The Mermaids are mythical creatures from the episode, "Welcome to the Bikini Bottom Triangle," There are 5 mermaids, each similar to Princess Mindy. They first appeared as antagonists, as they stole many objects from Bikini Bottom. Their reason for stealing the objects was so they could find something "cool" to wear. When they sung their song backwards, it returned the enormous pile of the stolen objects back to Bikini Bottom. They then decided to go to the mall with Pearl, because they wanted to find out what a mall was. Patrick had a crush on the Mermaids. Unlike Mindy, the mermaids looked confused seeing Patrick, when he wanted to hang out with them.
Like Mindy, Patrick had a crush on them. Apparently, Patrick likes mermaids.