calvus and breeding.

[steve]

Hi guys, i have a couple, black calvus , that seems to want to breed . they are garding a shell that only the female can get in . The male stays near the shell and won't let any fish get to close. The male, will sometimes put he's belly in the opening of the shell when the female is inside .
do i separate the parents from the eggs or wait till the eggs hatch ? do i just separate the male ?
I heard  that the male will sometime eat the eggs or even the fry. I also heard that you can leave them all together .
they are now all in my 120 gallon tank with 20 other tang and malawi cichlids. Should i take the shell and parents and move them into another tank ?
keep in mind i can't see inside the shell to see the eggs , if there is some .
can somebody explain me the process ??

thanks

Steve