Sure. It's always good practice to have the LFS
show you the fish eat before you buy it. Thats one of the reasons why I have a problem with buying fish online.
On topic, the lion could probably go another week without eating. When feeding, try turning the lights off, putting his favorite food in the tank and then moving out of the fish's line of sight and then peek around the corner to see eats or not. Might help.
The lion's probably still acclimating to his new home and doesn't feel comfortable yet.