I have a 12g nano dx and I have it set up nicely with some mushrooms a couple of candies a few colts a xmas rock a few polpe colonies a hammer and a frog spawn 2 small leathers a zenia a feather and a clam. I am still using the same light that came with it and the little skimmer plate that goes over the filter in take. Can anyone give me the reason why I should be using an external skimmer or any differant lighting than what came with it. I have had it set up for about 6 months now and everything seems to be doing fine. any advice would be welcome.