Hi, I am a new fish keeper myself and have had the same panic as you have had. I have lost 2 platies. My tank wasn't fully cycled before adding fish, but I didnt realize you could cycle without fish... anyhow, my ammonia levels have been through the roof for a couple of weeks now and it is obviously effecting my fish negatively. I am doing very frequent small water changes. I have Ammo-2 to de-toxify the ammonia. I bought a water conditioner thing called CYCLE which apparently adds a lot of the beneficial bacteria to the tank. And I condition any new water I add back to the tank. I have also tried adding salt chips (special aquarium salt chips) to the water, it decreases stress in fish, and raised the temperature a couple degrees. The remaining fish seem to be hanging on pretty well, and I hope they survive! But in general, start with strong fish like platies (I dont think gourami's are tough enough to endure the cycling process) and dont add any more fish until levels are constant. Good luck!