I have had a big head dendro in my tank for about 2 months and just had some questions about it. It looks like it is growing on a rock but is that just its skeleton similiar to frogspawn and duncans? Also they is a 1/2 inch of rock or skeleton between my 2 largest polyps and looks like there is only rock or dead skeleton between. If I wanted to frag off a piece would I cut down the middle or even though it seems like dead rock or skeleton is it alive?