a zebra eel is a great one and so is the snowflake. I have a snowflake in my office tanks and he knows when it feeding time, loves the freezdried jumbo krill. fun to feed.
Also triggers and lion fish are not always a good combo as the triger may pick at the lion, i would opt for a niger, crosshatch or a blue throat. I have kept all three in tanks over the years and found them to be great fish. My niger was the coolest as he had read teeth and a long tail fin.