It's obvious that guppies aren't hardy.. and with all the deaths I'm going to stick with other fish. I have two swordtails... one female one male.. two Dalmatian Molly one male one female... one golden sailfin Molly and 6 of her 3 week old fry. The pairs don't seem to breed for me. Looking for options for hardy easy to breed livebearers. Why won't the ones I have mate?