Thank your for responding. Your tank sounds like a great place for Endler's livebearers to hang out. It may be that your females just need a little more time to drop. You might find them a meaty food to supplement what you are feeding them with.  I would suggest one of the live foods available (maybe a few blackworms at a time, squirted into a soap-less, clean jar which is just 2-4 inches high. (The worms can't crawl away into the gravel and the fish can get at them.)

A frozen food, which can be defrosted, gently rinsed and fed to them could be bloodworms. Feed only as much as they can eat. If you handle the bloodworms, don't rub your eyes with your hands - some people have had nasty allergic response to that. Despite the cautions mentioned about the bloodworms (see also Immediate Help), a lot of Guppyloggers have borne witness to their usefulness as a food for guppies and P. wingei.

The reasons I'm suggesting the meaty food is 1. that it increases the protein in the diet and may help the female produce more fry at a time. Also, even though Endler's are very fry tolerant, a protein hungry adult will still resort to cannibalism. If the adults are sated, they will leave the fry alone.

For really cannibalistic fish, and there are livebearers like this, the trick is to fill the parents up to the point where they almost "waddle." After miserable failures with the red tailed Goodeid (Xenotoca eiseni) and Brachyramphis rhabdophora and near failures with the western Gambusia and Caracodon lateralis, I fed the adults until I wondered if they would explode. ;) Relatively good-sized batches of fry (for the respective species) were saved, even where there had be NO fry before, when the females had obviously dropped. (And the Endler's should be far, far "easier" to deal with than those species.)

It has been the experience of a number of aquarists that once one or more fry has/have been around in a single-species colony of livebearers (also in the case of many killies and some others) that very often the adults will come to accept those fry as just a part of their colony and environment. (There may be an issue with crowded sibling cannibalism later though.) I have seen this with a number of hard to save fry, including a couple of species where articles had declared (chuckle) that keeping fry with those adults was impossible. :)

Do you know what strain yours are? For instance, I have that old strain, where because of the founder's effect of having too few males, the double sword males now are as alike as the proverbial "peas in a pod." They are therefore very likely descendants of the original Endler's collected by Dr. Endler himself. Fortunately, they are very attractive "peas" and I treasure them. Scott Lockwood has informed me that they are "Peacock Endler's" which is a nice name and probably sells well. ;)

There are also several newer strains and some color morphs of Endler's around. Look back at Armando's fish pictured in the articles above or look (don't necessarily buy from there) on www.aquabid.com