Welp, it's like this. Not that you can't feed him goldfish, but you should ween him onto a frozen food variety diet consisting of krill,shrimp,silversides,etc. This will prove to be less of a hassle, less expensive, and probably more beneficial to the health of your eel. Well, maybe not less expensive but it won't cost much.
Feed him til satiation (look at his belly and if you think it's bulging with food then discontinue feeding). You'll be able to tell. I mean, it all depends on the size of the goldfish, which can have a wide range of sizes. Good luck with your beautiful eel. Watch out when he grows though. The one that ate my 8-9" lionfish when he got hungry did it very quickly. Talk about a crazy site to see. They're great as a single pet when they are large (kinda like having a dog) but when they get that size they shouldn't be kept with other fishes under a ft long. Then again, they may eat the ft longers depending on the shape of the fish.
ONE MORE THING: I'm not here to harp you but I wanted to be sure you were aware that the eel gets about 5ft long. Way to large for a 55gal. You will need at least a 150 to 180. I'd say get a 225 minimum when there full grown. The large one my friend had that ate my lionfish was in a 125 for a while and that was too small. It eventually hopped out and didn't survive. You can't really secure your top too good from an eel that is about 5ft long/5" thick and full of muscle. So if he doesn't like the small tank he's in then he will definitely leave.
[ August 28, 2001: Message edited by: skirk ]
[ August 28, 2001: Message edited by: skirk ]
[ August 28, 2001: Message edited by: skirk ]