Something real strange just happened in my tank. I bought 4 polka dot botias (Botia Kubotai) just about a week ago and today everyone of them died, at around the same time and, what i believe, the same way. Only the 4 loaches died, but all the other fish in my tank seem normal. Each loach was covered in this mucus that made their whole body look cloudy and when I scooped their corspes out in a net, the mucus stuck to the net as well as to the side of my tank. The way how only the 4 loaches died the same way and at around the same time just freaked me out. What kind of disease is this, how do I treat it, and are my other fish at risk of getting it.