Multie Parenting Behavior

Your right it doesn't really apply, he was introduced well after the colony was established.
There for he's clearly not actually a parent of any fry.

Getting back on track, I have had Fry grow into adult hood and chase the father out of the tank (found him the next day all dried up).
As to why yours chase their fry I have only one thought: Possibly, new parent syndrome.
I"ve seen a few times with angel fish and N. pulcher , they'll just eat their first few batches and eventually stop.

Have you had your Multies for long?
 
I'm misunderstanding you about the father being introduced later. He was stocked at the same time as the female. But I may believe they are new at parenting, although I really can't be sure because I bought them from locally from someone off another forum.
 
At least 2 dozen shells in the tank for 2 adults and fry.
 
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