The story could revolve around how the centaur baby interacts with its family and other centaurs, and how it develops its own personality and skills in a centaur-centric environment.
The main feature is its unique concept of centaur characters and their adventures. But a drawback could be that the story might get a bit predictable at times.
Maybe it's a tale of friendship and discovery as the centaur and the mermaid navigate through different realms and overcome obstacles together. There could also be elements of romance or a quest for a powerful artifact.
The littering sign might be a symbol of the need for environmental consciousness in the centaur's world. It could play a role in highlighting the importance of keeping their habitat clean.