Continuing a thread from elsewhere, I found these small "hairs" or "strings" on my purely indoors tree. They were just coming off leaves, off a branch, sitting on the soil, etc. It looked haphazard: two pics below:
The first thought was perhaps cat hair- and this made sense, as my cat really likes to try to eat and rub up against the tree. Another suggestion, though, was that it was spider-mite webbing.
I took a much closer look across the tree, and found multiple leaves with evidence of damage- some of it what a spider mite might be responsible for, but other leave scarring looking different. I tried putting a paper towel beneath the branches and shaking it a bit trying to get them to come off and have visible evidence, but that didn't work. I was also unable to find anything moving or mite-looking upon visual inspection of both the top and bottoms of the leaves. Here are some photos of some of the leaves where you can pretty clearly see some damage:
As you can see, the damage is there but not "everywhere," as much of the tree has green shiny leaves as Fukien should. I didn't see any of this until this last week or two, after I had repotted the tree into a new pot with some bonsai soil purchased from a high-end independent shop near me. So if there is some problem, perhaps the new soil brought it in?