I finally confirmed this bazaar behavior. Three months ago I purchased an all new tank, gravel, rocks, filter and heater. Moved the Red Zebra to this tank and she is still having babies.
We had six swimmer today. She has been doing this by herself in a tank with no other cichlid for over a year. I set up the fresh tank as a control to assure that we didn't have a small dwarf cichlid hiding in the gravel.
Please advise. This is really interested behavior. If you know of anyone who would like to study this situation please let me know.
I am assuming that she can store sperm for a very long period of time and use it as needed. I really would like to have this documented.