Masakana Koi ni Narimashita.

Iwai Shiori (35), a woman past her prime. When a man named Date Mizuki (27) moves next door, her dreary, unchanging life is turned upside-down! And the cause of this change… is the fact that she sees him as a fish!? But ever since she spent the night with Date-kun, she starts seeing him as a handsome man every now and then…!? Shiori's love story rapidly unfolds!