Start offering pellets every day even if he refuses, remove the uneaten after a while ...hell figure it out eventually... Most young pima die because they are not fed enough. They have a very fast metabolism at this size and thats y some consider them fragile. My pair accepted sinking pellets immediatly and id feed them 2-3 times a day. Grew them from the size of urs to 28" and 30" in less than 6 months on pellets. Super active fish and very rewarding to watch grow so quickly. good luck! Cute at this size... they start gettin scary as they grow lol... Very smart/aware specimen.... once they know u have food theyll follow u around as would any other "wet pet". Sooner u get ur guy on pellets the better, shouldnt b as hard as u think considering it was probably farm raised.
Thanks for your reply! The feeder fish that live inside the Arapaima's tank are the ones currently eating the sticks, so there's no need to remove any un-eaten since there's none haha. I really hope I'll be able to make this baby monster grow! So far it looks very healthy and it's eating like a pig. I'll keep you guys updated.
Cheers!