With the right environment, they feed quite easily.. but sustaining the bioluminous bacteria is the hard part.. I believe the part which lit up helps the fishes to get food at night and in the dark.. as mine always shine and flicker very brightly when they are feeding... but becos mine is a community tank though it is dimly lit, they still cannot make it long under community. Best is a dark species tank and they do well in groups of 5 and above..