The rainbow fish is shunned by others because it's different and won't share it's scales when asked to, and then it has to literally change itself and give away the physical attributes the others were envious of in order to be accepted. Friendship shouldn't work that way. You don't change your body to make others like you. Sharing is so important that you're literally not allowed to have anything of your own, it has to be divided? Even if the scales he gives away are meant to represent non-physical attributes (wealth, possessions) it's a socialist approach and not necessarily something to preach to children. Why does rainbow fish have to be liked in order to be happy? Why does everyone have to be the same (they all have one scale in the end) in order for them to get along peacefully?
I don't like it.