We wont hold your ignorance to propper feeding against you, as at least you where smart enough to ask for help. But please next time do alot more research ahead of time as they are living creatures, ask around here if you want to know more we tend to be helpful. But in this case take theCanucks advice he has one of the nicest/healthiest captive eels I have seen in a long time so he knows what hes doing. Also try to feed you eel either whole or only beheaded fish, like leave their guts in as they have alot of good nutrients in them.
But you shouldn't have a problem with him eating to much, they aren't as dumb as goldfish.
You should only feed your eel saltwater fish, freash water feeders and brakish feeders like reds and gold fish and mollies have way to high a fat content for marine diets. This excess fat is known to shorten a saltwater preds life significantly by causing a disease reffered to as "fatty liver disease" it essentialy destroys their livers. AS someone else said its like junk food, once and a wile is fine, but all the time would be like only eating junk food and everyone knows thats not good for you haha.