I recently noticed that my Red Swordtail (Xig) Molly has been staying in the corner. At first I thought it was dead because it stayed so still but after looking at it longer, it was still alive. I recently but rocks in the tank that I have already sterilized specifically for the tank. There is also an Albino Algae Eater, Seymour is it's name (which is slightly smaller than the Molly). I noticed after the rocks, it has become more aggressive and territorial. It's odd because when I first introduced them into the water, the Molly would mess with Seymour. After the rocks, however, Seymour because more aggressive. The pet shop I bought them from said they were community fishes. I just want to know why my Molly is staying so still in the corner? And why is Seymour becoming aggressive? Please help anyone!