They will need some type of filter feeder food like Phytoplankton. DT's is preferred becasue it is live culture but it's expensive and can be hard to find. Kents phyto plex is fine and available everywhere. There are many many others. Be careful of filter foods like microvert as too much can cause problems with amonia or nitrite spike as this is a meat product. You really do not need to give them very much food though as most corals get their nutrician from your lights, the filter food is just an additional source of nutrician not the main source.
