I have a 19" Snowflake Moray Eel, in a 125 Gallon. For Filtration, I have a 10 Gallon fuge reverse lit w/ Caulerpa, a 40 Gallon RDSB w/ 9" deep sand bed (This is a 18" diameter barrel), and a 6" deep fuge at the top w/ Cheatp and Caulerpa. Lastly I have a 65 Gallon sump (30 gallon actual volume), with a Euroreef RS180 skimmer. For tankmates, the Eel has a Niger Trigger (7"), a Miniatus Grouper (7"), a Reef Lobster (7"), a Sailfin Tang (4"), a Yellow Tang (5"), a coral banded shrimp (large). I also had a 3.5" porcupine puffer, but he wasn't competing well, so he's in the fuge right now. Bioload is astronomical, hence the filtration. The eel by itself eats 8 to 10 shrimp every other day. I would definitely upgrade the skimmer because you'll need bigger soon enough, even if you add nothing else. Any tank mates you add are going to be similarly demanding on your filtration.