First of all,i have crushed coral also and when
i got mine the lfs said to bury the tail,but i
tried and it wasn't happy were i put it so it
moved,and buried it's self,so i would say just
put it in. Second,they are fish friendly,they
don't harm the fish and the fish don't harm them.
Thirdly they are filter feeders. And last,but not
least i don't know about them and your craps,cause i don't have a crap of any type.They
do more harm than good,in my opion.