Something you can do presently is partition the tank. Provide a nice cave or hiding area where he can mozzy along without feeling preyed upon. You can use fake plants in a marine tank. Granted it's not as great as the real stuff, but it does provide hiding space and does give a tank without any good green stuff a nicer look. I can't remember the name...might be SeaGarden??? who have silk replicas of marine plants. Look very nice too. We once had a tomato clown someone brought in that took to one of these fake plants as though it were an anemone...LOL
. She would even try to 'feed' it by shoving food in it. So funny!!
The quicker you get him in a secured area, the quicker he'll come around. Puffers do very well in captivity once they are secured in their surroundings. It's not uncommon for puffers that are new to sort of 'pout'. Seriously. They have their tails tucked and they sit in a back corner with a puss on their face...LOL
. Don't really blame them. Remember...they were abducted from their homes. Sort of a guilty way of looking at it, but the knowledge learned may very well save their environment and keep these fish (and all fish) from disappearing.
Your situation reminded me of these photos I took at the SuperZoo trade show in Vegas this year. The lion in the photos did not move out of that position for quite sometime and he'd go back...LOL
. Mean while his thoughts of lunch is eating a dead shrimp. Though in this situation, the shrimp doesn't pay any attention to the lion. I don't think he would even without that sheet of glass between them...LOL
. I just thought it was funny how this lion was just so wanting to get at this shrimp, but he couldn't, but oh was he wishing. The other lions in the tank paid absolute no attention to the shrimp. Just this one.
We, as a people, know so much more about outer space than we do about our own oceans. This lack of knowledge can very well spell the dangers that lay in wait for us.
The oceans surely would swallow us before a rock comes down to smite the planet of it's life.