I am a registered breeder of wild type endlers. I never allow them in any tank that contains any other poeciliids. It has been shown that they will cross far too easily with guppies and I don't risk any crosses with any other common livebearers. I do keep some corydoras and plecos with mine but they also do fine in a single species tank. I find they do great at about 25C, 77F, in my relatively hard, 7.8 pH, water. I tend to feed mine a diet high in vegetable matter.
The biggest problem people have with endlers is that many fish sold as endlers are really guppy/endler crosses. That means that you cannot simply go into a pet shop and find any pure endlers. What you will find in most pet shops are things with names like tiger endler, which is a very pretty guppy/endler cross.
In general, you can treat an endler in much the same way that you would treat a guppy and the thousands of resulting fry will thrive.
