Man it's hard to get good photos of tiny fish like endlers . . . oh well, here's a shot I got of a single male. Keep in mind this photo is several times larger than real life . . .
Endlers -- They're actually not tetras; they're livebearers. In fact, they readily hybrid with guppies, and the hybrid is fertile. Which is why endlers and guppies shouldn't be kept together; you'll mess up your stock of both species.
Cherry barbs and swordtails would probably be ok (I don't think the swords would eat the endlers).
Anyway, the ones in my photos are male; the females are less attractive, and the shop didn't carry any (which pissed me off).