I should check out the java moss thing....what's a cycling tank?
hmmm
well thats a good place to start! =)
theres tones of stuff on the net about cycling a tank
basically, when a tank is new, the good bacieria hasnt had a chance to develop in order to break down fish waste into less harmful stuff; therefore, bad crap is in your tank that can kill your fish. baby fish are extremely sensitive to fish wastes, so having them in a fully cycled tank is a must imo.
putting them into a non cycled, new tank, is probably going to be a bad thing...thats why a breeders net in your exsisting tank (cycled) is your best bet
a breeders net can stress out the mother quite a bit, but if your able to time it, put her in there just before shes about to give birth (hard thing to time...cuz who knows??)
rocks work fine for holding bacteria, but its all a matter of surface area? more surface area = more places for bactiera to grow. your filter should have one of those sponge things in it, so i think youll be ok