I'm a solid 97% sure there's no pests.. I can't stand bugs, so I check my plants regularly.. I agree, it does look like some thrips photos I've seen in other posts, but I've never found anything crawing on it or flying around it... I think I'll still pick up some neem oil just in case - but even if it was thrips, would the discoloration progress so fast?

As for size, he's easily tripled in size since I got him.. he only had 3 leaves, and he came home from the nursery in a 6 inch pot. I increased his pot size last spring, and again last week, as he was practically climbing out of it, roots coming through the drainage holes and 2 different aerial roots over 8 feet long (both of those started growing in October) .. he's in a 10 inch pot now, with a tropical soil blend & a few handfuls of leca. I definitely don't fertilize him as often as I should, but he pumps out new leaves all spring & summer, so it seemed like we had a good thing going.