Interesting things to note in this chapter:
-The chapter starts with her reading a book about fish, which further indicates her trying to live as a "fish" to meet her mother's expectations
-Her mother is on the ground crying after her dad asked her is she ever tried to understand him. I know typically the first assumption when people enter this scenario would be he hit her, but if you notice there's no indication of that, or any violence on his part for that matter, which I think is meant to indicate that the dad, for all his faults, is the level headed of the two
-The dad also talking to Koto about how she views her mother may be an early indication about whether or not he thinks it would be better for her to stay with her or to leave with him, which is interesting in itself
-Interestingly, Koto both sees a cat and a fish that she relates to, perhaps showing her conflicting struggle between the two positions she wants to be. The fact she also sees a happy family indicates her longing for a normal life to some extent
-The joke about her taking him there on dates because she wants merchandise is funny, but I think that the real reason is that he reminds her of her father, who also took her to museums.
-Finally, MC's comment "You're a human," I think, is meant to further the symbolism. People aren't as clear cut as trying to live in a fulfilled role trapped to be on display for others or to try and be absolutely free in all other aspects. She's a human, a mixture of both elements. Interesting.