A theme for "Rumble Fish" is curiosity killed the cat. A good example of this is that towards the end of the book, Rusty and his brother broke into a pet store and the policemen shot and killed the Motorcycle Boy.
Another theme for "Rumble Fish" is that life isn't fair. Rusty wasn't born into a very wealthy family but that wasn't his fault. And when he was trying to fight someone, they brought a knife and he only had his hands.
One character trait of Rusty James is that he's a troublemaker and irresponsible. In the book, Rusty get's in lots of fights, skips school, and got expelled.
Overall, I liked the book. I liked it because there were some plot twists that I didn't expect and it added a sense of redirection. I wouldn't recommend this book to anyone who is in middle school because of the violence that is displayed in it.