I got 3 platies a week ago, and they are currently kept in my 10 gallon/ 41 liter QT tank. Every once in a while at least one of them seems to be having some white, stringy poop, even tho most of the time the poop looks normal. I read that might be a sign of intestinal flagellates. Should I just keep feeding them varied, vitamin rich food, like a couple of books suggest, or get some antibiotics (I can get antibiotics quite easily for professional reasons)? I've been feeding them a varied diet for the week I've had them, including mixed flakes, granules, veggie tablets, freeze dried tubifex, and so on.