I first tried starving for 2 days. Then see if they will eat pellets. If they eat pellets after 2 days don't offer other foods. Just feed pellets. Chances are that will not work. If it does you are very lucky.
Stuff shrimp with pellets and feed that the next day. If your arowana is used to eating shrimp this should be easy. You can do this for 2 or 3 days.
On the 4 th day pre-soak pellets in shrimp water and feed pellets. Do this for 2 days. If your arowana doesn't eat for those 2 days don't feed the next day and try soaking pellets again the next. If he doesn't eat at this point you may have to be more patient than he is. Continue to offer pellets until he eats them soon he'll be eating like a champ.
If you are getting a new arowana don't feed him for the first 2 or 3 days. Then try the pellets. If the arowana is new you want to make sure he is eating something. If he won't eat pellets then try market prawns.
If your arowana only accepts super worms and you are worried about nutrition you can try an old trick I used to use. I would put the super worms in the freezer and wait a few minutes until they stopped wiggling but not frozen. Then take them out and inject them with liquid vitamins. I used Boyd's vitachem. Once the arowana is used to the taste of the vitamins in the superworms then try soaking the pellets in vitamins.