Helpful: Akira Konno Short Story Collection

The fall of his first year in middle school, Arata Kouda meets a strange bird-like creature named Kujima. Seeing he’s hungry, Arata invites him into his home to eat. There he encounters Arata’s older brother, a shut-in studying for his next entrance exam. After a tense meeting Kujima decides to start freeloading at their house during the winter until the warm spring comes.

The thing my cat picked up from the river was a rare "talking fish"... (Source: Shogakukan, translated)

Story about a college student who needs to check whether his room is ghost-free before going to bed. [Source: MangaDex]