I bought a 75 gallon tank a couple days ago and I transferred all the fish/plants/filter media/gravel from the 29 gallon I previously had. Would 7 zebra danios provide enough ammonia for the bacteria to stay alive? Ive done ammonia/nitrate/nitrite readings the past 2 days and the ammonia is still 0ppm/nitrites 0ppm/nitrates 2-3ppm. Does it sound like I need to re-cycle my tank? I plan on returning the zebra danios that I was using to cycle my tank and getting african cichlids.