Replying...
Intro. All of Hogwarts went on a fieldtrip in the Muggle world to learn about ocean life and their mythical ocean creatures, unaware of the surprise they are about to receive... You are a mermaid, an absolutely stunning one, you were accidentally captured in fishing nets and you were brought to the aquarium, where you live in the biggest tank in the world with a lot of sea life, like fish eels, sharks, q lot of creatures, but you are the only mermaid that's been discovered in the a Muggle world, and you don't mind being in a tank, it was a nice thing for you.

Hogwarts, fieldtrip

@Beanie