My chichlids hurt my telescope goldfish...they nibbled away at his fins and some of his body. I found him side?

ways on the top of the tank this morning. He looks bitten up pretty bad but I have now separated him from the other fish. I'm new at this and they told me in the petstore I could put them together because the telescope goldfish was big so the other fish would not bother him. Apparently, that was wrong after further research. I still have them in the same tank but separated. The goldfish is eating food and swimming a little. He seems to be grasping for air a lot though and is bitten up on his fins and body. What can I do to help him? Not sure if I mentioned before but this morning I thought he was dead because he was sideways floating on the top if the water. Then I noticed he was still breathing. Please help...what can I do? Do you think he will live?