Try Hikari Food Sticks
http://www.hikari.info/tropical/t_06.html
My little leichardti Arowana I bought at 3 inch starting eating them on day 2 of being introduced to them. The first day he just would mouth them and chew and spit back out but on day 2 he was mostly eating them and now he gobbles em up...
I normally make him eat 3 or 4 sticks before I finish feeding with other food items such as frozen and or live blood worms, shrimp meat, baby night crawlers and crickets once every week or two. I give him a good variety. Hes only had feeders one time since I have had him. I gave him baby guppies one time, but don't plan to give him feeder fish too often.