I have a 25 gallon tank with 4 male guppies. I added them together with Tetra Safe Start 7 days ago, following all directions from the thread here (24 hours after dechlorinator, no water changes etc). I know you aren't supposed to test with TSS but I did and mid-week it was showing about 0.25-0.50 of ammonia, no nitrites and no nitrates. Fish seemed fine, eating and active. When I tested today there was 0 ammonia, 0 nitrites, and 0 nitrates. There are 4 Amazon swords (bought potted), 1 corkscrew Vallis, 1 java fern and 1 anubias. I have attached a photo of my tank so you can see how heavily (or not) it is planted. (Ignore the cloudy water, it's clear now). Something must have happened beneficial bacteria-wise as the ammonia has disappeared. But where to? I haven't done any water changes and have been feeding daily. If the plants aren't enough to be absorbing the nitrate, then where has the ammonia (and the ammonia that the fish continue to produce) gone?