Thanks (again)
@Humblefish. I'm not totally sure that it was the same behavior, but it also wasn't that far off. By the time I added the (overpowered) power head into the tank, the fish seemed pretty exhausted/lethargic, so any behavior was more along the lines of fighting to stay in control than it was about anything intentional looking... Still; there was a lot of rubbing against things (first the clay pot, then the tank bottom and sides). I do recall thinking, "Is that one just really itchy, or...".
There may have been discoloration - I don't know. This is where I don't have enough experience to compare good coloration to bad.
I've gone ahead and dosed in 12.5mL of
Kordon's Copper-Aid. The instructions called for a temperature raise to at least 82F, so I did that beforehand. I also added a tiny power head (
Aqueon 500) and set up the HOB filter with just the mesh pad (no carbon).
The blenny seems to be doing fine right now. He was actively eating earlier when I put in some mysis shrimp - popping out of his cave to gobble up pieces that float by. I can't say for certain, but it does appear like his breathing is a bit heavier than when we first got him. That may just be me looking for signs, however.
Hopefully the next few days are less chaotic. I'll keep an eye on the QT tank and will update with status one way or the other. Many thanks to the entire [HASHTAG]#reefsquad[/HASHTAG] for the help; to say I was underwhelmed at the response from the LFS would be to put it mildly, so I'm beyond appreciative that I continue to find proof that I can count on the members of this forum as I progress through this journey. Cheers.