i dont think they are hard at all to keep, in fact i believe most will say they are very hardy. i feed mine pieces of fish food, frozen fish food . they are growing like crazy! and pretty much eat anything that touch their feeders
I have had one in my tank for about 5 months now not neon green but color shouldn't matter) and it's growing well. Seems like an easy coral to keep. I feed it about twice per week with cyclops, krill and coral frenzy mixture. Here is a pic.