Im going to be putting a snowflake as my first fish in my tank,they can live for 20 plus years and i hope he does live that long.My tank is also a 120 gallon and im going to go with a lion fish as well and some corals and other fishy. I dont know about keeping two,but I have talk to lots of people who have a very nice tank with a snowflake eel one guy told me it had been a year and even his cleaner shrimp was still alive, I hope it works out because snowflakes are my favorite,but I want lots of other stuff too.