Livebearer Disease or something else?
I've lately lost a few Platies and Endlers, while my other other supposedly more sensitive fish have been fine. The livebearers had been fine for quite a while, until I added some new Endlers from a chain store, and then they started dropping off one by one starting with two of the Platies. There have been no real external signs, they each just started acting listless and faded away over the course of a day or two.
I read about Livebearer's Disease, and heard differing views on it being caused by internal parasites, a lack of electrolytes in soft water, and bacterial infections. Thus recommended treatment varied from raising hardness, to adding Start Right, to giving medicated fish food. Or it could of course be something else other than that supposed disease of course, but it's nevertheless only affecting the livebearers.
My tank uses pressurized CO2 so the Ph does vary, but my other water conditions seem fine and hard, so far as I can tell and so far as my crap test strips measure it.
Should I try the medicated fish food? Or just leave it alone and hope the rest will be okay?