One possible theme could be fear. The night often represents the unknown, and in a short story set at night, fear of the dark, of what lurks in the shadows could be a major theme. Another could be isolation. At night, a character might feel more alone, cut off from the rest of the world.
The theme of mystery is very likely. The night has an air of mystery, and in a short story with this setting, there could be an unexplained event or a series of events that the reader has to piece together. Also, redemption could be a theme. A character might have made mistakes during the day and the night gives them a chance to make amends or find a new path.
One possible theme could be the mystery of the night. Since it's a 'fish night' story, the night might add an element of secrecy and the unknown. Another theme could be the relationship between humans and fish, especially if there are humans involved in the story.
One possible theme could be food and celebration. Lobsters are often associated with special occasions and a sumptuous meal. So the story might revolve around the joy and togetherness that comes with a lobster - centered event.
One possible theme could be change. Since night and day are two very different states, the story might explore how things or people change from one state to another.
One possible theme could be mystery. The full moon often creates an air of mystery, and the story might revolve around something unknown that occurs on that night.
The theme of self - discovery could be present. For example, a woman who takes night walks to think and figure out her life path. Also, a theme of resilience. A night woman facing difficulties at night, like a single mother working at night to support her family, and still being strong.
One possible theme could be heroism. There were many heroes on 9/11, from the firefighters who rushed into the burning buildings to the passengers on Flight 93 who fought back against the hijackers.
One possible theme could be despair. If the story is about an unending difficult situation, despair might be a central feeling. Another could be perseverance, as the characters in the story might be trying to get through the 'endless night' so to speak.
If it's based on a real story, possible themes could include survival. For example, if it's about a real - life disaster or a dangerous situation that people had to endure during a particular night.
Love at first sight could be a theme. The sudden and intense attraction that leads to the one - night encounter.
Another theme might be mystery. It could be that on that night, something strange and unexplained occurred. For example, an object disappeared or a strange noise was heard throughout the night, leading to a search for answers.