I regularly stocked my display with live phytoplankton (3-5 varieties depending on how fast my cultures regrew) live zooplankton (depending on my culturing tanks and availability, 4-6 varieties both bottom dwellers and ones that stay in the water column), live Amphipods, 1-3 types (not sure about this as I bought a mixed culture to start my own culture so it could still be all 3 or just down to 1), live small shrimp varieties such as Mysis, as well as various types of worms/snails which act as detrivores but second as a food source. I haven't found a small enough live fish that is salt water and has the proper nutrient spectrum for me to add any live feeder fish yet. Of course I also grew marco algae like Gracilaria and Ulva, to use as a "live" food for tangs and other herbivores. All of these things second as coral food, big mouth corals can eat the larger stuff, where as filter feeding corals or corals with tiny mouths can eat the phytos and newly hatched zooplankton or young amphis etc.