The best method is is too use a pvc elbow instead of a orange pot for convicts. They will lay the eggs in there.
After two days remove the pvc elbow and put it in a separate tank with an air stone and raise the fry yourself. (Use maroxy for fungus control) Just put another pvc elbow in there and they will spawn again in 3 to 4 weeks.
That way the parents stop killing each other. Just remember to use a net to protect your hand from the attacking parent when you retrieve the eggs.

I got my wrist nailed many times and I can say from experience that convicts do indeed have many sharp teeth.
Ouch!!!
EC