I'm not sure what kind they are - I just inherited them from someone whose newts had an unplanned pregnancy. I think they are one of the red or firebelly types. They have been living in a small aquarium with aquatic moss, and they started out eating zooplankton. However, these three have gotten large and are bullying their two smaller brothers, so I had to separate them. All 5 have been eating bloodworms, so they are big enough to handle those. Anyways, I thought there was concern about raising them in a finer substrate because they would eat it accidentally. Also, they seem completely aquatic to me, so I don't think that a moist soil habitat would be good enough...they have their gills and whatnot. When transferring them to the bigger aquarium, they were squirming all "fish style". I could be wrong, but I think they are too young to be out of the water.
Their habitat is a 25 gallon aquarium with rocks piled up out of the water at one end, and a platform also out of the water at the other end. There are also some elodea plants in there, and some of their original aquarium moss for them to hide under. There is a waterfall style filter.