A few things you may want to know........
They are very similar to wild guppies in appearance.Females looks just like guppy females,too.
Now,to an untrained eye they look the same,but if you pay some attention,all males look alike in their body coloration and paterns,unlike guppys which are all different.
Also,a wild guppy doesn't have the bright colors that a endler does show.
One of the problems you might run into is the lack of any females.Breeders do not sell them.For these you might have to go on line and get them.
Why you ask.....Well,they are virtually extinct in the wild,and breeders who have them won't part from the females,so they can regulate the price and rarety of these gorgeous fish.Like they told you before,they will breed with any strain of guppies,so try to keep them apart.