if you are having trouble raising the fry i find it is most often a water issue. The fry are a lot more sensitive that the parents, so even though the parents are ok, the fry wont be. I found that when i was using tap water for breeding the parents were ok but the fry would die, which would trigger an ammonia spike, dropping the water quality even more and more fry would die until the spiral had completed itself and none were left. I had to treat the hell out of the water to make it safe for fry, now i run RO so its much easier
In terms of breeding, I always suggest using proifits from breeding to upgrade. This is good for two reasons, firstly, there is no major cost, you are making money from breeding that goes into breeding, keeps my girlfriend off my back anyway

the second is that you will have to wait for the funds to build up, meanwhile you are learning the ropes and perfecting your skills. once you have the $$$ to spend on some decent breeders then you will have the skill base to draw upon to get the new ones to breed.