I hardly ever see a post here about someones eel that doesn't say it got out and died or was put back. I have not had that experience yet but consider as mentioned in the last post a real consideration for one buying a eel. If you have hang on equipement (which I do) it is virtually impossible to close down the top completely, so you have to be concerned a bit and watchful (I have become so paranoid I look down on the floor before I step in front of the tanks they are in).