About the only bad thing, you only see them at night. They start coming out at around 9pm, and my timer on my aquarium turns my lights off at 9:30pm. 9:00 is the earliest I've seen them out, but usually once the lights go out, they come out. They even feed out of my hands. Fire eels ore pretty tame, and let you toucch them and feed them out of the hand. I can't quite touch them yet, but not much longer should be able to. Once they get used to the owner, they will love you to death.
PS. Fire eels really aren't true eels, but fish. Just for your info.