I have some rainbows I just recently bought and have quarantined them. I have noticed their poo is white and stringy, which leads me to believe it is an internal parasite or internal bacterial infection. Does anyone know how to tell the difference and what kind of medicine and where I can find it? I have heard of medicated food, but not sure if that is the way to go, and don't know where to find it. It's not at Petsmart or Petco for sure.