Hello all. I have a 3 year old heavily planted 20 long. current occupants are 7 harlquin rasboras, 8 pepper corys, 1 dwarf gourami and 1 peacock gudgeon that will probably by gone very soon. I had 2 other peacock gudgeons but they recently passed. I've had all of these fish over two years and have been battling a mystery disease basically since this tank was setup. Many fish had/have white stringy poo. My fish used to flash occasionally but I don't think that was out of the norm. I have tried quite a few things to battle suspected parasite infection and other complications. I've used paraguard, prazi pro, general cure, kanaplex, metroplex and furan-2. All my fish survived for quite long time with the only symptom of have white stringy poo....that is until about a month ago. Whatever is wrong in my tank is getting worse. My previous two peacock gudgeons both rapidly became emaciated and passed. My 3rd and last remaining peacock gudgeon developed a small black mark kind of on his back, it grew larger and larger, then a white filmy spot formed on his other side. I treated with furan-2 and the white spot went away but the black spots grew and he became more and more emaciated. He is now no longer eating and is skin and bones and probably has a day or two left. I'm noticing more and more fish that never had white stringy poo now have it. I've used medicated fish foods and all the works to treat internal parasites. I just now stumbled on the camallanus worm in my research (not sure how I never knew about it before) I'm fairly certain this must be what I have since all the other medications did not work and camallanus is known to be resistant to everything i've tried. I'm also wondering if I might have a slow strain of columnaris.... these two diseases are tough to diagnose. Any thoughts and suggestions would be appreciated.