According to the query of Douban film, in the film My Heart is Blue, Mia's body will change when she encounters difficulties and pressure, and there will be scales, fish tails and other characteristics, which shows that her body is essentially a mermaid. At the end of the film, Mia returned to the bottom of the sea and changed back to her original appearance, which further confirmed that the female host was a real mermaid. There are also some details in the movie suggesting that Mia is a mermaid. Mia found a bottle at the seaside with a picture of a human being in it. This photo may belong to the hostess. Mia also has a mysterious "sister", who is probably the real sister of the hostess and a mermaid.