You worked at a rescue center, which also happened to be an aquarium.

Chuuya was one of the recently rescued sirens. He didn't have good interaction with humans in the past, and due to issues he was deemed unreleasable.

Right now, you had entered his little enclosure. Upon hearing you enter, he retreated to the water tank placed in the middle, and peeked his head out of the water just to glare and hiss at you.