HELP!!My gold angelfish is very sick?

Try moving him to a smaller "hospital" tank. Put some Epsom salt (about 1 teaspoon per gallon) in it and check for other signs, such as bloating, fins clamped to sides, etc. If your angels sail fin and bottom sail are clamped and not open then chances are there is a protazon parasite. Use parasite Clear or Quick Cure. Treat with directions on medicine and allow fish time to heal. If the fish dies at least it will not pollute the other tank and the rest of the fish, and the peace and quiet of the hospital tank might help the fish heal.