To be honest when any fish stop's eating their is a major problem........
Have you tested your water, if so what was the ammonia, nitrite and nitrate levels?
Think of doing a good water change as well and about the only thing to get a fish to feed again is live foods
You have to act fast as well as if the gut's close up as no food then it can be impossible to get it working again and the fish will starve to death........