Nice save I hope he recovers. He may take a few days to start eating. Was he eating at the fish store at all? If so ask them what he was eating. Although they sound like morons it wouldnt hurt to call and ask them. Other from that freeze dried blood worms because they float or live brine shrimp are usually very enticing to a baby aro. To get my babies to start eating I take a little pipet like what u do water tests with and suck some live brine into it and gently squirt a few brine close to their mouths. Once they work up a good appetite you can stop doing it his way
GOOD LUCK