Seeking help, a small fish appears among the Rainbow Fish and his friends. He has lost his school and wants to stay with the shimmering fish. However, the spiky fish does not want to accept him into the school, and the Rainbow Fish does not dare to contradict him. But when a dangerous predator fish shows up, he finds the courage to help the little fish after all. A heartwarming story about respectful coexistence that delights even the youngest readers.