The Rainbow Fish was a beautiful fish with sparkling silver scales that made the other fish admire him. However, he refused to share his scales and play with the other fish. The Octopus told him that he needed to share his scales if he wanted the other fish to like him. The Rainbow Fish began giving small silver scales to the other fish, and though he lost his beauty, he gained friends and happiness.

1. Rainbow fish
by Marcus Pfister
adapted by Aida Muntané
Once upon a time there was a beautiful fish, with sparkling
silver scales. He was very beautiful. The other fish admired
him and his scales, and called him “Rainbow Fish”. The other
fish​ ​asked him to play “Come, Rainbow fish, come!” but he
didn’t want to play.
One day a small blue fish asked him for one of his silver
scales. The Rainbow fish was angry, he didn’t want to give any
of his scales. The blue fish told the others and none of them
wanted to play with the Rainbow fish.
One day the Rainbow fish asked a Starfish why the other fish
didn’t like him. The Starfish said to him that she couldn’t
answer that but the Octopus could help you.
The Rainbow fish found the Octopus and asked her “Why does
nobody like me?”.
The Octopus said to him that he must give a scale to any fish
that asked for one. You may not be the most beautiful, but you
will be happier. The Rainbow fish thought about it.
Then, a blue fish asked him for one of his silver scales, and
then he decided he would give a very small silver scale.
“Thank you so much!!” said the blue fish.
Another blue fish asked for a silver scale, and the Rainbow
fish gave him one silver scale.
Finally the Rainbow fish had only one silver scale but he was
happy and he was playing with the other fish.
http://www.storylineonline.net/the-rainbow-fish/