IMHO the main problem connected with keeping endlers with apistos is their rather intensive metabolism. That's probably why Mike asked about tank dimensions. In a small tank with considerable amount of endlers there could be problems with organic waste and nitrogen compounds level should be systematically measured. But if the tank is big enough, with good filtration, every week water changes and the substrate vacuuming there's no problem to keep endlers with apistos.The Apistos ate most of the young that were born but never bothered the adults.