They can vary in shade, but if it's a lot lighter, it may be stressed. When Carl, my tile, gets stressed, he can turn a very light tan. You can train the tile to handfeed because it's so small. However, you're asking for trouble if you hand feed a bigger eel. It happens plenty, but it's just not worth it to me. Between their poor eyesight and possible aggressiveness, the odds suck just enough to respect my fingers. They can give nasty bites with teeth that are pointed back, to hold food in, that you can either break or have to open the eel's mouth to get your hand out. A bite from an eel can, and often does, create a very aggresive infection that can cause loss of limbs or even death if untreated. So there's your weights to balance. Remember, an eel can go months without eating. A mistake I have made, is trying too often to get new my eel to eat and actually making it not want to eat because I wasn't giving him enough space of his own.