Arowana Not Eating for weeks

Hi Bros,

My Aro not been eating for weeks already... once a few days will eat only 1 piece of MP or 1 SW and stop eating again... Change water regularly... Any possible that something is wrong with the fish throat or mouth? It used to eat alot... Very responsive everytime i thrown the MP or SW into the tank. Out of sudden one day it stop eating and behave this way... Now everytime it eats, it would eat and spit out a few times untill the food become smaller or softer then it will swallow it and then stop eating again. Fish still look healthy & swim healthily though... Please help....