Filter feeders only - very difficult. You can dirty a clean reef trying to keep them fed. The only time that I ever saw one that was happily fed was when we had a maxi-jet un-suction and stir up the sand and turn the tank 100% browish-grey (anyone remember the maxi-jet and suction cup days?).
You used to see them in stores quite often 10-15 years ago for pretty cheap, but I think that common sense has kept them in the ocean recently.