Hi, I have just set up an Aquatop 3.9 gal aquarium. It has a gravel substrate and planted. I have talked to several people in lfs's and everyone gives me different advise. Tank is about 2 weeks old. I did buy three small green tiger barbs on about day 5. They only lived 1 week. I did 1/3 water changes every other day. Water was treated for Chlorine/chloramine. Plants are growing well. I have been testing water and yesterday and today, ammonia was negative, Nitrites were 2.0 ppm and nitrates were 5.0 ppm. My question is; Will the tank continue to complete cycle without fish and what do I have to do? thanks, Barbee236