When you say that "he wasn't at the point mine appears to be at" do you mean yours was just thin?
I did see a bit of actual swallowing going on there, with quite minimal backwards shimmying, to be honest. Mine shimmied much, much more when I had it.. of course, still a long way to go though.
What food was that? Have you tried finely shaved/minced clams yet?
Don't get me wrong, it's a first step & there are some good signs.
I'm not being critical as much as just pointing out some observations and concerns.
The coralivores that were eating clams from that Asian guy were attacking those clams and ripping them to shreds to get mouth size pieces.
I'm pretty sure a Lavartus was one of the fish he had kept for 3-4 years.
It was a reef builder linked story.
I remember doing some research on those species of clams & they could only be bought bulk from some Asian country and were only sold by the pallet at a crazy cost.
You might try to find as many different clam/mussel species as possible for him to try. Maybe at a whole foods store or fish market.