Update: it’s been a week. The red growth (which looks fuzzy up close) is the same. He is still swimming and eating but he seems a little sluggish. I noticed a couple scales missing along his back and at his throat yesterday. This morning he had a white poop (see pic). I rarely see him (or any of my fish) pooping at all so that is not normal. Also last week one of his girlfriends laid eggs (one of them does that every month or so) and instead of fertilizing then and then hanging around and tending to them with mom for a couple days he ate then as she was laying them.
So far I did a couple water changes. Nitrates are down to less than 10ppm. I also treated two days with amoxicillin — Saturday and Sunday, then did 50% water change yesterday — as I was concerned about the whole tank and the guy at the fish store said that wouldn’t hurt them. I was concerned because on the same day, about 5 days ago, a hole appeared in the fin of my pleco and then the distal part fell off, and the mouth of one of my cardinals got stuck open and his abdomen became sucked in. The pleco seems fine (see pic), and even the cardinal is swimming around normally, even though he looks odd. I even say him eat, he just sucked a piece of food in.
I’m thinking the professionals introduced something into the tank? They did a good job, just always risky to have someone else do things.... Or maybe not.... At least I’m set up so I can change the water myself again (I can hook the hose to the shower so don’t have to carry buckets.)
In any case I’m thinking I should go ahead and set up a hospital tank and treat him there? With Maracyn?
Thanks again for the advice so far.
