I've had my girls for sometime now and I come home today and shes swimming vertically basically not using her back tail. I had my water tested today and everything is in normal range. Any ideas? I do not see any bite marks on her, nor have I see her get chased around. I'm lost on this one. I've been doing some research and the closet thing I can see it being is swim bladder disease but she doesn't have all the systems of that either. If she does have that wouldn't I have to see something in the water change like ph amonia, nitrate something?