new tank -- is it cycling?

Question
Hi, I just set up a new 10 gallon tank a week ago, and added 2 zebra danios 6 days ago. On day 3 one of the danios died and I bought 2 more at the pet store. I have one live moneywort plant, a regular power filter, and an under gravel filter with 2 heads with zeolite rocks in it. I'm wondering whether the zeolite is disrupting the normal cycling process? I've been testing my water daily and it is still reading 0 for ammonia, nitrites, and nitrates. I'm not sure what is going on, or why my one fish died if the tank is supposedly clean. Should I take out the zeolite filter heads and replace them with carbon? Or just wait longer? The 3 fish in there now look ok, although the 2 newer ones still have red gills (which they had already at the store).

Answer
5 zebra danios are too much for a 10 gallon tank.  Take back the two that you just bought with the red gills, it sounds like they are already sick.  Just use the 1 danio that you started with.  It takes 6-8 weeks to cycle.  For the first week or so you may not see much ammonia, then it will spike in the 2-4 week range...after that it will start to go down and you will see nitrite. What kind of test kit do you have.  If it is a strip kit, return it and get a liquid reagent one.  Change the water when ammonia gets to be .25, nitrite .25 and nitrate 10 or more.  Check it daily. Red gills sounds like ammonia poisoning to me. Do not add more fish until you get 0 ammonia 0 nitrite and 10 or less nitrate after you go through the spikes.