Hi Jimmy-Thy're actually not real eels. They're engineer gobies or aka eel gobies and are very peaceful. In fact, they can be considered as reef friendly.
The tricky part was getting them into the same tank with 2 triggers and a porcupine puffer, so what I did was start them in a 10 gallon as babies. Then moved them over to a 55 gallon and eventually into the 125. You need lots of rockwork and coral for hiding. I made caves for them knowing that no other fish could get to them and eventually the triggers gave up and everyone got along.