Sounds most like a bacterial infection that is affecting the fish, try daily water changes see if this helps any. Try some frozen brine shrimp & garlic (most good stores will sell it) the garlic has a natural antibacterial properties, which will also help, plus it does entice fish to eat.
Out of curiosity what cichlid is it? I know some americans will "shake" when annoyed, my oscar does it when I get the water change buckets out.