fragging devils hand while still in the tank

[Sense of nature]

I searched& didn't really find any solid answers to my question
I have a large devils hand that needs to be trimmed back
Anyone know for sure if I can frag it while still in the tank? It's attached to a large rock that is not removable
I'll run carbon obviously , but not sure on how toxic it is
My tank is 220 gal
Thanks
Robert

 

[Sense of nature]

Got my answer, mods please close