Aquarium by David Vann tells the story of twelve-year-old Caitlin, who lives alone with her mother. Her mother works as a docker, and they live in subsidized housing near an airport in Seattle. Caitlin’s mother avoids talking about her past and her own family, leaving Caitlin desperately wanting to know where she comes from.
The haunting tale opens with a conversation between two strangers, Caitlin and an elderly man. Both are visiting the aquarium. The elderly man begins to ask the girl many questions about herself, making her feel slightly uncomfortable. She decides to leave the aquarium and go stand outside, waiting for her mother to pick her up. Caitlin and her mother have a close relationship and spend most of their time together, aside from when her mother goes on one of her dates.
Caitlin is a lonely young girl, and as she continues to visit the aquarium, she forges a relationship with the elderly man. Obsessed with fish, she loves animals in general. She dislikes eating meat and plans to become a vegetarian when she is older. She talks to the man about her love for fish, and they talk about traveling together to Louisiana to see the marine life. As they continue to get to know each other, Caitlin starts to reveal more information about herself as well as her mother, and their life together.
The narrative jumps forward in time, told from the perspective of Caitlin who is now thirty-two years old and reflecting on her childhood. She feels angry about the lack of caring and concern she experienced as a young girl, feeling so vulnerable in the world.
She thinks back to how her relationship with the old man developed, in direct response to her need for love and affection. Even at twelve years old, Caitlin knew something was wrong, but feeling that she needed the old man, she went along with it. When Caitlin’s mother finds out about her interactions with the old man, she is horrified. She immediately calls the police and tells them everything.
Interrogated by the police, Caitlin is terrified that she will be separated from her mother. After getting her account of recent events, the police go to the aquarium to apprehend the old man. When they arrest him, Caitlin learns that the man is actually her grandfather, desperate to reconnect with her. Caitlin’s mother and grandfather clearly have a strained relationship, and Caitlin wonders why her mother would keep him a secret from her for all these years.
She soon learns that her grandfather left her mother and their family when she was young, abandoning them with no money. Caitlin’s grandmother was very ill, and Caitlin’s mother was forced to quit school in order to care for her. In spite of it all, Caitlin still desires a relationship with her grandfather, which enrages her mother. She begins to regularly abuse Caitlin whenever she is triggered by the events of her own childhood.
She forces Caitlin to take care of her as she did her own mother, determined to show the girl what her childhood was like, and why she refuses to allow her grandfather back into their lives. Over time, Caitlin’s mother and grandfather come to an agreement, which results in them moving into his house. Caitlin’s mother is apprehensive; she has always wanted to live in a house, though she knew she could never afford it. Caitlin finds her grandfather is more forthcoming about their family history, and she enjoys listening to his stories. She feels that she is finally learning about who she is and where she comes from.
Throughout the novel, Caitlin explores a romantic relationship with a friend from school, and the girls begin to fall in love. This also leads to Caitlin’s first sexual experiences.
Caitlin and her mother move in with Caitlin’s grandfather just before Christmas. In spite of her mother’s objections, they decide to bring some festive spirit into the house with a Christmas tree. While they are on a family outing picking out the tree, Caitlin’s mother and her grandfather get into an argument, and Caitlin’s mother reveals that she had to work as a dancer in order to pay bills when she was a teenager.
When they return home, Caitlin and her friend take a hot bath together to soothe their frozen limbs. While they are kissing in the bath together, Caitlin’s mother walks in and makes it clear that she does not approve of her daughter’s behavior. She forbids the girls from seeing each other again, turning violent as she attempts to throw Caitlin’s friend out of the house in a fit of rage.
Caitlin’s mother explains that she was often referred to as a lesbian in a derogatory way; she wants better for her daughter. Caitlin’s grandfather convinces her mother to accept her daughter for who she is.