Go to ebay, search chalice food, buy a few of those. Remember to acclimate the pods.
But I agree that you probably added the fish too soon. If you manage to get him out, put him in QT and train him to eat prepared foods. I started mine with Ova, never seen a fish turn that down. Then I added some garlic soaked frozen cyclops. After that I garlic soaked a variety of frozen foods: Reef Plankton, bloodworms. After a few weeks I got him to eat PE mysis. Now he eats frozen to supplement the pods. Some guys get them to eat BBS, but I don't really see the nutritional value in them (unless you gut load, but that was too much work for me)