Oh, I don't know about that, they're pretty smart fish. I think he's acclimated to his human's hand and, rather like a dog or a cat, has come to enjoy the attentions. I know that with the eels I learned to handle (after getting over my significant fear) they had no issues with parasites. One of them was in a display where we'd gone ahead and put in some cleaner shrimps, thinking they'd become a meal for someone eventually (1500gal tank). That never happened, but the zebra was especially fond of getting the attention every time someone had to dive in (for cleaning, it's hard to reach the bottom of a 1500gal tank). That thing was easily as thick as my thigh, and that is pretty thick!
I would really love to see a video of it, especially because we don't normally think of fishes as animals we can form a "real" bond with, you know, like we do our dogs, cats, or birds.