Oh good! I learned the hard way, I had a 5 gallon going for about a week before I added 3 neon tetras. 1 died almost before he left the bag and the other that night, only 1 survived. So me and my stupid self thought it was the temperature fluctuations, it was very cold outside when I bought them, so I go somewhere else and buy 6......they all died within the day. I felt soooo bad, I ran out and got a water test kit, yep ammonia killed 'em, all but one.
A dumb, rookie mistake, never again. That is why I asked, hope I didn't offend.
I bet he is having fun checking everything out.