What would you do with this dwarf lion???

Saw a dwarf lion at LFS 6 weeks ago - put him on hold and picked him up last thursday (9 days ago). I could not get him to eat. LFS said he was eating mysis and squid at the store. I do trust them as i have been going to them for a while now and have never had any issues with anything from the store. I tried mysis and the squid for the first week, as well as krill (waved it around his face on a feeding stick), then tried soaking the above in garlic, and still no dice, he wont eat. I went back to the LFS today and explained to them I am having issues with the lion eating and they stated they would gladly take him back and try to get him eating again and then let me try again. They also suggested I try some ghost shrimp, which I did when I returned home, and he did end up eating them! but not in the way you would normally see a predator fish eat. I feel like his vision might be off (kinda has a slight haze to his eyes) He doesn't seem to hunt at all, he just hangs around and when they come close to him he doesnt move, even let one of shrimp crawl all over him! I watched him for 10 minutes after i put the ghost shrimp in and nothing happened, i then checked back in a few minutes and ghost shrimp is gone and i could a part of the shrimp sticking out of his mouth
So my question is, if this was your lion, would you guys give him back and let the store try to continue feeding or would you see if you could keep him going in your tank?
I knew ahead of time some dwarf lions are tough to get them to eat, and i dont have a problem working on that, but i am a little nervous that he is so lethargic (more then a normal lion is).
I am kinda attached to the little guy, but if the store is willing to take him back and get him eating again, or if he dies while back at the store they will credit me the cost of him.
Sorry for the long post :-/

 

Here is a pic of him. Tank parameters are good
ph - 8
sg - 1.023
amm/nit - 0
nitrate - <10
The only tank mate is a small damsel that is not bothering him

What would you do????

 

Unfortunately, that's the nature of the beast; dwarf lions tend to be ambush predators, waiting tirelessly for prey to get close enough that they can grab it with little effort on their own behalf. If you want an active hunter, you would probably better appreciate a grouper or trigger, providing your tank is large enough.

As for feeding, you got him to eat shrimp. That's a good start. Keep giving those, and start mixing the other foods with them.