i've been fighting bacterial disease for well over 2 months in my freshwater planted tank. I made a mistake of purchasing 3 guppies in an auction which were probably infected. Anyways, after the dust settled, i'm still left with this strange disease that causes a reddness on my fish's stomach near the anal. I imeddiately got rid of the swordtail because the red was BRIGHT CHERRY red 8O and the scales on that area was coming out. (it was an awful sight) I thought i got rid of the problem, but i'm seeing other fish with the same symptoms except less red. What is this and what medication treats this disease?