As far as something to get him to begin eating, go to your local fish store and pick up some live ghost shrimp. Before you give the ghost shrimp to the lion, give the ghost shrimp a good meal. This is called "gut-loading" the ghost shrimp so that it is more nutritious when the lion eats it.
When he does start eating and recognizing you, feed the lion krill, prawn, mysis, clam, mussel, small bits of squid, and other meaty variations.