Had some I had removed most manually sometimes they would come off easily anyway as for pitho crabs I had small growths of algae and ordered one and yes it definitely ate the algae but for some reason it liked to hide itself in the sand and would burrow below coral I have on the sand bed tossing them around it would add small pieces of substrate to itself and rest.in the sand bed hidden coming out to look for food I did not leave it in the tank it was like a bulldozer at times.

