So, I think Blush has fin rot. I noticed black edges on her fins today, and I'm QT her because I'm not sure if she's developing new coloring or if it's fin rot. None of her fins seem damaged, but I wanted to get her separated from the tank (10 gallon divided) to be sure it didn't pass to the others. Don't worry, I will be keeping my eyes peeled for any signs of illness in the other boys. Besides Aquarium salt, which I've added to her QT, what else might help?