I am relatively new to the hobby, 8 months. I have recently had to move my tank to another house whilst I had building work done, this went without a hitch. When I brought the tank home I decided to give it a revamp, a clean and New substrate, because of massive alge buildup. New water was added, treated for clorine and I also added more bacteria. This was 2 weeks ago, all original fish are fine, but I added a new black neon 2 days ago and found it dead this morning, could this be a form of new tank syndrome? Should I wait a few days more before adding anything new?