Yuki Nijino's manga / #Guardian(1)

Didn't read this in chronological order lol whoops. I couldn't handle the suspense. And well, angst. - Dude's apartment have bad feng shui so his mother buys him a koi fish artifact to help with it. And it works. There's also a sprite living in the artifact. He falls in love with the sprite. Kekw he fell in love with an inanimate koi fish.