They will eat the asterina and when there is none, they will eat meaty frozen food. They are a species of Harlequin shrimp. The problem with the typical Harlequins is that they only eat asterina and will starve if there is no supply.So you have to rehome them or get everyone to give you asterina.
Mind you, this is what the article says, not from experience.
http://reefkeeping.com/joomla/index....efkeeping-101-