tank won't cycle right and I have fry!?

[rainbowguppy]

I started a brackish 20g tank 3 months ago. First started fishless cycle using ace pure ammonia. Followed instructions from online. After over a month of nothing but ammonia I switched to fish cycle. Purchased three "male" guppies from petsmart. After a while of low ammonia .25ppm max several people recommended getting another fish saying it didn't have enough ammonia to start cycle. Was weary but followed advise and got a female(planned to have females and males anyways). I had also started using Stability product to help cycle. Supposed to cycle tank within 7 days. Doubled the recommended dosage after talking with product company and them recommending it. Have been using Stability for 10 days now. Two days ago(sometime evening/night before last) one of my "males" gave birth to fry. I didn't even notice until yesterday morning. Got a breeder net and put all 6 fry in to keep them from getting eaten. Was told not to do water changes because it would mess up cycle(unless fishes lives were in danger) and definitely not to do water changes now with fry as it will kill them(it killed my neighbors fry). Ammonia went up to .50 yesterday. Yesterday saw beginnings of nitrites(finally) of like .5(barely even registered). Today see nitrites of between .25 and .50(closer to .50) but ammonia has not gone down. It is still at .50. Will the ammonia start to go down soon? Worried about the fry. Have no where else to put them. Should I continue to dose with stability? All the fish(especially the fry) seem to perk up when I dose with it. How long do I keep dosing with it? Until the tank cycles? What are the chances the fry will make it through the cycle. They are all swimming and eating well. Cut down feeding adults to every other day as of three days ago but feed fry a couple times a day. Also ph has started fluctuating as of three days ago but was told that was normal when cycling.

[frefal13]

Not doing water changes when cycling with fish is a bad idea, yes water changes slow down cycles but ammonia spikes also kill fish so you need to keep the ammonia at 0.25ppm at a max. Cycling with fish takes a longer time than fishless, and it is more work and more stressful for you and the fish. Also I have never heard to not do water changes with fry...most fry need large frequent water changes to keep water quality very high so they survive. Water changes should not kill fish unless the new water is significantly different from the water in the tank, or it was not dechlorinated.
I suggest doing a water change to reduce your ammonia and nitrite levels. The ammonia will go down eventually but your bacteria are just starting to grow so they is not enough of them yet. Also note that the nitrite reducing bacteria takes longer to grow than the ammonia bacteria. I don't know how fry will do in a cycling tank.
I also suggest looking in the live bearer section and look at the fish sexing sticky so you can determine which fish are males and female. It is usually pretty easy with live bearers who are large enough to have fry.

[Lady Hobbs]

Moved this to cycling section instead of saltwater.

Right now, just keeping the fish alive will be the trick. You will have tons of fry but if the adults die, you won't be having any so I should concentrate on the adults first.

I would do water changes that bring the ammonia down to .25 and continue with regular doses of Stability. Not much else you can do when you cycle with fish.