Platties are the most individual livebearers i've ever seen (or my dad has, for that matter) i've kept Guppies and Swords in the past and they were all the same; the females were lunky and stuck together, the males were too 'enthusiastic'. the Platties i own now are completely different; i have one male who either can't or won't breed, and another who's got that on his mind constantly. i've got two Girlies that wanna have fry, one that doesn't.
adding to their numbers might help, you may get a female your boy now likes, and a male your girl now likes. or maybe they're just eating all their babies!
