I don't know what the spot is; I doubt if anyone can tell from the pics. That would determine if you moved fish to a QT. Does the spot look like a possible parasite? It could be an isopod or similar parasite, take it off with a tweezers. It doesn't look or sound like ich to me. No reason to quarantine if you aren't using meds. If it isn't festering or spreading and doesn't look like a separate parasite-type critter; I'd just ignore it. BTW, it won't hurt, but there's no real reason for a fish with HLLE to be in a QT.