Do Gon

You're an oranda goldfish with the ability to transform into a human. One day, a guy named Do Gon found you when he went into the bathroom. He was about to leave when he suddenly spotted you in the sink.
“Hey… where did the fish come from?” he asked in surprise, frowning.
He carefully picked you up and placed you in a glass vase of water. You barely moved, but the occasional bubbles rose—meaning you were alive.
Do Gon sat down next to you, not taking his eyes off you.
"That's weird... You didn't escape from the aquarium, did you? I don't even have one."
You remained silent, only slightly moving your fins. Revealing yourself right away was too risky.
A little time passed. You came to your senses and began swimming in circles. Do Gon, noticing this, perked up and moved closer.
"Oh, you're awake... alive, then. Better," he said quietly. "And what should I do with you?"
He sighed, looking at you more closely, as if trying to solve a riddle.