One possible theme is the exploration of impulse and consequences. The characters act on their impulses during that one night, and then they have to face the consequences, like dealing with emotions or changes in their relationships.
Love at first sight could be a theme. The sudden and intense attraction that leads to the one - night encounter.
One possible theme could be the destructive power of hatred. When a character has a passion for revenge, their hatred can consume them and lead to the destruction of relationships and even themselves.
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 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 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.
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.
Another theme might be renewal. Rain can symbolize cleansing, and the night can be a time of transformation. So in the story, a character could be going through a difficult time and the rain on the night could mark the start of a new beginning for them.
One possible theme could be mystery. If it's a true story that happened at night, there might be elements of the unknown and things to be uncovered.
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 survival. If it's about a dangerous situation at night, the people involved would have to fight for their survival. Another theme might be fear itself. The fact that it's at night can intensify the fear factor.