they'll eat any variety of flakes, micro pellets, brine shrimp, bloodworm, daphnia.... live or frozen, they're not fussy!!
also feed peas once in a while to help prevent constipation
just get normal frozen peas, drop them in some boiling water for 30 seconds or so, then squish them so you get the squishy inside bit, if nescessary chop it up into little pieces and drop them in the tank
I feed my small fish (neons/embers) Tetramin Tropical Granuals. When the food sinks, it gets caught up in the filter flow and gets driven around the tank. The fish go crazy for this and dash and dive around, a little more naturally than just waiting for the food to come to them.