Good news! Ammonia is low, NitrIte is low and I have yet to test the NitrAte in the tank. I removed the UG filter and installed the AquaClear 50 (200GPH) Power Filter. I then added 2 ghost shrimp and 4 neon tetras to the original leopard danio (the danio is becoming a fin nipper so I think i'm gonna have to get more soon). The only thing I'm having a problem with is the heater! My first one broke, not sure on the wattage. Then I bough a 100 Watt one that couldn't get it over 45. Then a different 100 Watt one that would get it around 60. I even tried using them both together! I now have a 200 Watt submersible filter that got it up to 60 degrees farenheit and now its down to a steady 45. It is a 20 gallon tank. Any idea on whas wrong?