Copepods

[Treebeard]

My significant other picked up a couple of nice surprises on the way from home work yesterday. She picked up a Green Mandarin Goby and a Tang (she forgot the name, but think it is a Powder Brown, or Naso).

About the Mandarin, from what I have read he will prefer copepods. Do they grow naturally in a sump? If not, where can I purchase them and how does one propagate them? Are they easily visible to the naked eye?