It's usually more humane to the fish to cycle the tank without them in there. Ammonia is generally bad for fish and a high enough amount will kill them though if you have enough plants and do frequent enough water changes it can work, at least according to what I've heard others say. I know nothing about how well this TSS+ or even what it is, but keep an eye on those ammonia levels. It does seem correct that you wouldn't see anything else at this point. It takes time for the bacteria which convert the ammonia into nitrite, and then, nitrate to populate.
If you haven't I would suggest reading a guide on fishless cycling of a tank vs fish in and make your decision on how you want to proceed.