I thought fire shrimp is pretty common. I kept 1 before. It jsut hide in the rocks all the time. End up my wife scold me for buying something that hides and cannot be seen.
The only problem I see is that if I set my dosing only at certain times. The left over food in the tubing will spoil since its not kept refrigerated. For continuous dosing, its not an issue.
Henry did bring in small ones before. He says that have to train them from young to eat frozen food. If the shop brings in adult ones, then they won't eat frozen food since they are already grown up eating SPS.