Save the garlic salt for garlic bread,and find out what it was eating before you acquired the aro.Give it time try keeping the lights off check water give it food it knows, they usually will go off a hunger strike for cricket.
A big fish like that probably spent alot of time in his old tank. Now hes in a new place and moving a big fish like was probably pretty stressful on him. I wouldn't worry to much he'll eat soon enough then look out! I never feed mine feeder fish but you might try throwing feeders in there if all else fails. Because you can throw them in and when he wants to he can feed on them. But quarantine them first.
its a large old and most likey stubbon fish. he needs time to adjust. give it a month before i would start to worry, add some black water extract and maybe a few tankmates that will pig out to get the appetite flowing. Many years ago i sold a 21" silver to a mates uncle... it didnt eat for a month and a half and then one day it just decided it was over his hunger strike.
good luck mate ... post up some pics
I think its just a case of patience. Dont hasstle him give the tank some space for a while so he doesnt feel watched all the time and back off the feeding attempts, give him a few days and then ry again, it usually works.