If you are feeding twice every day, you are feeding your eel way too much. Here is something I read about something called power-feeding the other day. I know you said you are not feeding over abundantely, but I thought I would put this out there for everyone's info.
"Offering copious amounts of food at excessively frequent intervals will make the animal grow very quickly, especially if power-feeding begins when the anuimal is very young. While power-feeding does cause rampant growth in the musculature and skeleton of the moray, it cannot increase in the development rate of the internal organs and brain. The end result is a very large bodied, yet frightfully unhealthy specimen that is ultimately doomed to a short life." p89 Keeping Moray Eels in Aquariums, Phil Purser ( I dont think SWF sells books, so I hope I am allowed to include that reference )
I have found the above to be the best book I have seen about morays.
Try 2-3 times per week as much as it will eat - as recommended to me by AW2x3.