My recommendation would be to try target feeding it small pieces of cut up white shrimp, available at Safeway or fish market; buy shell on, then thaw, remove shell, and cut up into small pieces; throw pieces ahead of aro as it swims to stimulate attack response. Aros will often pick up shrimp off tank bottom too, so you can leave pieces in for a while to see if the aro will eat them. After 30 min remove any uneaten pieces. Try this approach morning and night.
Because your fish has been on live food, it may take a while to get it to accept something else.
If you just want to see your fish eat to put your mind at rest, you can try feeding it a few crickets. Most Asian aros find them irresistible.
Any photos of the fish?