About 3 weeks ago I got a new 29g tank, with an aqueon filter that came with the tank and a heater. I got blue tank gravel, 4 fake aquarium plants, an air pump with a fake clam that opens and closes with the bubbles. The guys at the local stores told me I could start adding fish after 24 hours. Well within a few days I had 2 guppys one a turquoise male, the other a yellow tail male, a balloon Molly, and an angel... Less then 72 hours later the angel was very sick and dying, that's when I found out about the cycle you should allow your tank to go through, so now I've been doing regular partial water changes daily. I have since been given a second Molly, this one black, a fancy cobra guppys, and a pleco algae eater... The turquoise guppys chases the cobra, who chases the yellow tail, who chases the balloon Molly, who chases the black Molly, while the pleco hides near plants. Everyone but the pleco is always nipping at the bottom fins, near where the poop comes out, of the fish its following, also pulling the poop right out or off. I also invested in an ammonia test kit (the angel died of ammonia poisoning I'm told) and a pj balance test kit, as well as "ammoniasafe" tablets made by "tetra" to detoxify dangerous ammonia, and "startzyme" tablets also by tetra, which is a complete water conditioner with beneficial Bacteria. Before that I used aqueon water conditioner. My ph balance is around 7.4 according to the test thing. But even after using the recommended amount of startzyme and doing 20-50% water changes my ammonia level stays near 0.05ppm which the test kit says is not good. I've been using the ammoniasafe tablets, and that lowers it to the safe level for a few hours. As I stated earlier its been about 3 weeks since tank set up, and in that time I've had a cloudy looking slime on the gravel, which I was told is to much bacteria, so I used a gravel vacuum thing to cle an the majority of it up. The ammonia test thing is one u stick in the tank and leave for up to a year, with it constantly testing. The oh one is the same, except lasts only up to six months. So last night before going to bed, as has become routine, I dropped a piece of an algae wafer in the tank for the pleco, gave the rest if them a lil punch of topfin tropical colour-enhancing flakes, checked the ph balance(was approx 7.4) and the ammonia level (was in the "safe" zone which the kit says is <0.02ppm, when I woke up the levels were approx the same though the ammonia one is starting to change colour to the "alert" level of 0.05ppm, but hadn't gone there yet. But the yellow tail(who was acting normal last night) was dead and stuck to the filter... The top of him, which was a silverish is now a brownish, and bluish right below that. I do not know why he died and am very sad. Any ideas? And why does my ammonia level keep rising to the alert level(0.05ppm) despite the startzyme and ammoniasafe and partial water changes?