There is a guy on here who had one that was very close to 40 inches. Beside it was a small Corydoras which was dwarfed by the eels size. I never heard of a fire eel eating other fish.
Also depends on who they've grown up with. If they have been with some small fish since they were very small, like mine were, they pretty much left them alone, even at 16 inches. But if I added guppies, they would probably become a meal.
is that a pic of fire eel looks wierd mine is black with a red stripe on top and bottom of body how long is yours???? what will it eat???? mine pisses me off only eats live ghost shrimp every one keeps telling me thats bad he'll catch a disease but i dont know what to do.. tried to stop feeding him live and he almost die of starvation....wtf????? any ways size/diet????