I didn't know whether to put this here or in molting but my crab just made a small hole. I have an ISO but there is currently a crab molting in there. It is 12 gallons. Maybe 10. I still saw him through the hole but he was 2 or 3 inches down. Not being buried yet I lifted him out and into the ISO with the other crab that was molting. I don't know if he is preparing for his 2cd molt in the last 6 months or if he just wanted to dig himself a little hole. Should I keep him in the ISO or regular tank?