So, I've had mollies in my tank for about a year. No problems. I added several fish (after quarantine) around Christmas. Today I saw one of my mollies acting WEIRD. It is just spinning around. I've never seen anything like it before. Tank is over 10 years old. Parameters are normal, except calcium and alkalinity (380, 8) which I'm already addressing. Does anyone have any idea what in the world is going on here? I've already figured out that she's probably not going to survive. But I'd still like to know why.