I take care of a big one at work and it is very mellow. The tank houses, a skeletor, zebra moray, dwarf golden (which is also huge), and a full grown snowflake. The snowflake is the meanest by far. All of them are over three feet and the skeletor is the biggest at about 4 feet and pretty thick, much thicker than the other three. The golden is the smallest and most passive.
They share the tank with garden eels, shrimpfish, a tang, and a copperband. There are urchins, snails, and hermits as well and none of the eels go for anything. They've been together about two years. The eels eat mainly whole peeled shrimp with some clam mixed in.