I just got 6 Gold Pristilla Tetras, all perfectly fine when I first put them in the QT tank. While they dont seem stressed (they're out exploring the smallish space), I've noticed one has had it's tail shredded, and hides in the shadowed area behind the driftwood in the tank, while the remaining 5 stay near each other on the other side of the tank. :'( Is there anything that could have caused this sudden outcasting? will this change eventually/with more fish added (I plan to have a full school of 8-12) or is this one doomed to exile or being picked on or worse? ... oooooor am I over dramatizing this?