Can you take the rock out? If so you need to be very careful and get under the foot.
I just fragged 4 of them myself. I try to keep mine in clam shells cuz right now they're in my 24g with alot of chalice and acans and I dont want them to move. I just set up a 12g nano for them to be by themselves.
I also thought the shells would be easier to get them out. Well they really suck on to whatever theyre on.
I had a cpl go on the rock and removed them by getting my nail (I have long fingernails) under the foot and prying gently taking time.
I used different methods with the shells. 1 I couldnt get out it was to stuck but about a day after me bothering it trying to get it out it moved on its own.
I did try a frozen fish food pack (didnt have ice) on its foot but it didnt work for me lol.
I cut 1 of the shells and it cracked all over and got the nem out like pealing a hard boiled egg. When I did this I noticed when I had it upside down the weight of it plus my prying under the foot a little made it realease so the next one I turned upside down and pryed carefully and it popped out pretty easy.
I had 1 that was embedded in a hole in a rock so I took my bonecutter to the rock.
I dont think it's a good idea to cut them in the tank on the rock. On Kraylens video he says to seperate the halves. They also should be dipped in lugols for 5 minutes or so to help them heal.
If anyones interested in putting them in shells (sometimes they move out but they usually stay. If I see them escaping I put them back lol) I found cockle shells to work good. I got some at my LFS and some at a hobby lobby a craft store. You just want the plain shells not laquered. Cockles are usually white and pink or yellow.
You want them big enough for the nem to lay out in.
Heres some picts of some of mine in shells.
I hope this helps. They arent easy to get off so be carefull you dont injure them or the foot in the process. Go slow. If they do get injured put them back and wait a few days before you try again.
kass