I have two eels in my 72 gallon one is a snowflake and I think the other one is a white mouth but I am not sure. They are both about 9 or 10 inches. The white mouth was in the tank for about 1 month before I introduced the snowflake. The white mouth actually just let the snowflake share his den and now they are best friends. They fight for food sometimes though, so make sure each eel gets food. Be careful at first because when I first put the snowflake in, the white mouth wasn't too happy about it. Also watch ur nitrates because they eat a lot and make a mess too, especially wen u have double the mess. Hope this helped!