Are you sure all of you guys are talking about the same crab? Ciliopagurus strigatus is commonly called the cone shell hermit crab and its body has evolved to be very thin to fit into cone snails. They will not accept any other shell in the wild, not sure about captive specimens, but mine only take cone shells.
Calcinus elegans, is the holloween hermit crab, which is just a color variety of the electric blue hermit. Everywhere except Hawaii the orange is replaced by the electric blue color, but they still are classified as the same sp. I have both that I collected in Hawaii over a year ago and again collected 5 of the cone shelled hermits on my last trip. I keep them in my zoanthid tank and have never had them bother the zoos. They are ok algea eaters, but are better scavengers and I have seen them take sinking pellets that land on the zoos, which may be what the one in the picture is doing. They are a pretty small harmit, max size is only about 3/4 inch across the carapace. Very cool hermit if you can find them, I have never seen them for sale though.
Do You own the one in the photos?
Are you looking to get some?
Or do you want/have the C. elegans?
Interested because I have them if you want, and curious where you bought them if you have the one in photo.