Get a plant! They're like the best thing for a tank! They basically eat nitrates and ammonia, remove CO2, and put oxygen on the water. Get the right kind though, unless you want your fish to eat it! Do plenty of water changes (when I had my tank I did 25% a day until everything was balanced out) I use purified water from my sink (removes chlorine, fluorine, and adds minerals) and Stress Coat+ (does all that the dechlorinater does and adds a slime coat to the fish, which relaxes them) I approve of my methods, and will start a thread on how to balance a tank (as I've successfully done it three times and know the matter inside and out) my forte is in bottom feeders and livebearers (my first time breeding, have learned much about guppies and platys) I will begin it now!!! ^^