the water definitely looks a lot better in my window tank this morning- very clear. Minimal smell. All five of my cories eagerly came up to the front to eat spirulina wafer (I give this to them once a week). Even Fabio came to eat! and was drifting around the tank in his old manner.
I did notice over the past few weeks Fabio sometimes gets twitchy. Jerks around and dashes across the tank, then acts normal again. I thought maybe he was just getting old and experiencing some kind of fish dementia. Um, probably not a real thing. Some of my cories occasionally flash against objects- I thought this was from irritation of fine debris getting stirred up out of the substrate, as I didn't see any signs of ich- no white spots on any fish. So I hadn't done anything because not sure what it was. Now considering parasite treatment because of their skinniness, I read the back of API General Cure package again. And something about the description of gill flukes clicked. It's probably what all of them have. I dosed the tank this morning.