Is she still eating OK in general? Still no clamped fins, and will come out to be active regularly? From what you've said, Sammi is a shy fish- her tank was rearranged, making it not as familiar as before, as well as having more current from the new filter. Not sure if this could make her shy again, until she gets used to it. As long as she's not acting obviously ill, and she's still eating, I would just keep an eye on it, and not worry too much. As far as the less noticeable gill movement when breathing- you said you're running Purigen now, correct? That boosts tank redox, and the added HOB filter would make more oxygenated water, as well, which means less effort to breathe. Goldfish, especially single tails, are coldwater fish who prefer temps to be around 68 degrees or below. Warmer water holds less dissolved oxygen, and the goldies can notice this. Goldies are also a fish with a heavy oxygen requirement. The higher temp water before the purigen and additional surface agitation may have made her breathe just a little heavier to get oxygen- add the stuff that boosts the tank's redox, and she breathes more lightly. The moor wouldn't have as much as an issue with this, as fancies are better with higher temps. Both are extremely hardy, and very adaptable, though. Does she look like she's gasping, or just not breathing as hard as before? I don't know if this pertains to you at all, but, sometimes with my goldies, they don't have very much mouth or gill movement at all when they're being kind of lazy, and they're breathing just fine. You can see them breathing very obviously when they are being active, but, not so much when just hanging out or coasting around. I run purigen, have some anacharis in the tank (heavy oxygenator, and nitrate sponge), run a HOB filter, have a bubble wall in the back, and a bubbler decoration toward the middle, so the water is highly oxygenated. From my experience, goldfish not doing a noticeable, rhythmic breath in, breath out pattern like mammals do is pretty normal in well oxygenated water. I do see that type of pattern when they're going all kamikaze around the tank, eating, or practice spawning... not so much when they're just relaxing and kind of lazily swimming around.
