lol shes hungry and they compete for food .Far as laying on her back if they mated then she would be exhausted and that behavior would be normal as she was very tired. Are the large anough to feed them some bloodworms or even red worms ? If so feed her and him until thye are fat and full and see if they start to get along better. Let me know how it goes . they like a variation of meals although yes they will eat practically everything . i feed my African Clawed frogs ( different frog but same appetite ) small feeder fish night crawlers redworms shrimp and bloodworms . I have 5 in my tank . they get along beautifully but they do fight over food at times . they do not get hurt but once they are good and full the fighting stops and they hang out together peacefully .