Hugo the Hippo(1978)

Sharks in his harbor inhibit the Sultan of Zanzibar's trade, so he imports twelve hippos to chase them away. But once the sharks are gone and the novelty of the hippos fades, his people stop feeding them and they roam into the city looking for food causing some destruction. Because of this, the king's adviser Aban-Khan has them killed, but one little hippo, Hugo, survives. A group of children finds Hugo tries to hide him, but he is discovered and tried in court for the damage that his fellow hippos caused. The children get the Sultan to appear on Hugo's behalf, and after his powerful speech, Hugo and the other hippos are seen to be the injured parties. Hugo is then released and the children take care of him for the rest of his life.